Sort publications by
Journal of Inborn Errors of Metabolism and Screening, Volume: 9, Published: 2021
  • Editorial Letter to the Special Issue on Newborn Screening in Latin America (Commemorating the Silver Jubilee of the Latin American Society for Inborn Errors of Metabolism and Neonatal Screening - SLEIMPN) Editorial

    Queiruga, Graciela; Borrajo, Gustavo JC; Cornejo, Verónica
  • Website www.emergencyprotocol.net to Support Prevention of Metabolic Emergencies in Patients with Hepatic Glycogen Storage Diseases and Fatty Acid Oxidation Disorders Letter To The Editor

    Souza, Carolina F. Moura de; Oliveira, Bibiana M. de; Schwartz, Ida V D.; Derks, Terry
  • A New Fluorescent Method to Detect Sulfamidase Activity in Blood, Tissue Extracts and Dried Blood Spots Original Article

    He, Xingxuan; Schuchman, Edward H.; Simonaro, Calogera M.

    Abstract in English:

    Abstract Mucopolysaccharidosis type IIIA (MPS IIIA) is a lysosomal storage disorder due to the deficient activity of sulfamidase (SGSH). Traditionally, measurement of this enzymatic activity has been performed using a fluorescently (4-MU) labeled glycoside substrate. While this substrate is inexpensive and readily available, the current method requires a 2-step procedure that is performed over 2 days. Here we report a new and simplified procedure using the 4-MU substrate. Major advantages of this assay method over the existing fluorescent method include a single step vs. 2-step procedure, an incubation time of 1 hour, and high sensitivity. The reaction is also run on UPLC equipment, which is available in most research labs and permits separation of the endogenous, autofluorescent material from the 4-MU signal. This assay method was developed using the MPS IIIA mouse model, and was validated using mouse plasma, liver and brain extracts, and dried blood spots. Human MPS IIIA skin fibroblasts and dried blood spots also were used to validate the method.
  • Molecular Diagnosis in an Argentinean Mitochondrial Disorders Cohort Original Article

    Martinez, Nerina; Rosales, Julieta; Medina, Nancy; Perez-Maturo, Josefina; Salinas, Valeria; Zavala, Lucia; Vega, Patricia; Rodríguez-Quiroga, Sergio; Morón, Dolores González-; Kauffman, Marcelo A.

    Abstract in English:

    Abstract Mitochondrial diseases are multisystemic disorders characterized by an impairment of the mitochondrial respiratory chain. Diagnosis requires an approach that involves a high index of suspicion, molecular techniques and a careful selection of the tissue to be studied. Our goal was to develop and implement local strategies for diagnosing mitochondrial disorders, by standardizing procedures of molecular biology and nucleic acid sequencing. A prospective, analytical, observational study was conducted in a cohort of, a total of 82 patients with suspected mitochondrial disorder who were treated at our hospital between May 2008 and June 2019. We developed molecular diagnostic tools that included classical monogenic techniques and Next Generation Sequencing. We characterized the neurological and extra neurological manifestations noted in our cohort. Following the proposed algorithm, we obtained a molecular diagnostic performance of 54%, identifying mutations in 44 patients. mtDNA mutations were identified in 34 patients. Structural rearrangements in mitochondrial genome were found in 3 and 7 in nuclear genes, respectively. Our results confirm the utility of the proposed algorithm and the molecular tools used, as evidenced by a high diagnostic performance. This is of great value to a more efficient and comprehensive medical care of patients and families affected by mitochondrial disorders.
  • Parenting Styles and Coping Strategies in PKU Early Detected Children Original Article

    Campos, María L. Pardo; Enacan, Rosa; Valle, Maria G.; Chiesa, Ana

    Abstract in English:

    Abstract Phenylketonuria (PKU) requires tight control to prevent neurocognitive impairment but reports show that patients may present mild cognitive defects related to higher impulsivity. We hypothesize that chronic intervention may influence the parents and child bonding and the child´s resources to face problems. To describe the PKU parenting styles perceived by the children (PS) and their coping strategies (CS) assessing their relationship with impulsivity, 30 early diagnosed and adequately treated PKU children and 30 non PKU aged-paired controls (CG) were compared. The Argentine Children´s Coping Questionnaire, Argentine Scale Perception of the Relationship with Parents, WISC IV Comprehension Subtest, and CPT II test were administered. PKU PS were based on control: strict to pathologic in the mother and acceptable in the father (both p<0.05 vs. CG). Children significantly sought greater support and showed less emotional control when facing conflicts. These characteristics positively correlated with maternal control r:.383 and r:.398 (both p<0.05). Impulsivity was higher in PKU (p<0.05) but didn´t associate with PS or CS. Maternal strict control wasn´t linked to the higher impulsivity found (possibly neurobiologically based). Nevertheless, if both factors are present, patients may develop a psychological and/or behavioral trait of greater dependency and impulsivity that must be considered in their follow-up.
  • Lesch-Nyhan Disease and Its Variants: Phenotypic and Mutation Spectrum of Hypoxanthine-Guanine Phosphoribosyltransferase Deficiency in Argentine Patients Original Article

    Laróvere, Laura E.; Fairbanks, Lynette D.; Jinnah, H. A.; Guelbert, Norberto B.; Escuredo, Emilia; Becerra, Adriana; Kremer, Raquel Dodelson de

    Abstract in English:

    Abstract Hypoxanthine-guanine phosphoribosyltransferase (HPRT) deficiency is a disorder of purine metabolism responsible for Lesch-Nyhan Disease (LND) and its variants, HPRT-related hyperuricemia with neurologic dysfunction (HND) and HPRT-related hyperuricemia (HRH). The objective of this study was to characterize a cohort of Argentine patients with HPRT deficiency diagnosed in a single center. Results: Twenty nine patients were studied, including 12 LND, 15 HND and 2 HRH. The average onset age was 0.64 years for LND with motor delay as the main manifestation, 8.84 years for HND and 2.5 years for HRH; nephrological manifestations predominated as presenting features in these variants. The average diagnosis age was 3.58 years for LND, 17.21 years for HND and 2.5 years for HRH. Clinical heterogeneity was more evident in HND, even in members of the same family. All patients presented hyperuricemia and no detectable HPRT activity in erythrocyte lysate. The molecular study allowed to identify 9 different mutations in HPRT1 gene from 24 patients (11 independent pedigrees) and to establish genotype-phenotype correlation. In conclusion, this study describes the genotypic/phenotypic spectrum of HPRT deficiency in Argentine patients and highlights the need to increase awareness about the suspicion of these diseases, especially the LND variants with high clinical heterogeneity.
  • Determination of Reference Values for Alpha-N-Acetylglucosaminidase Activities in Patients with Sanfilippo Type B Disease and Control Population in Colombia Original Article

    Borda, Johana Ramírez; Uribe-Ardila, Alfredo

    Abstract in English:

    Abstract Sanfilippo B is a lysosomal disorder characterized by the pathological accumulation of heparan sulfate. It is caused by mutations in the NAGLU gene that codes for the alpha-N-acetylglucosaminidase enzyme. The objective of this study was to determine the reference values and frequency of Sanfilippo B in Colombia through an enzyme analysis of leukocytes extracts. We aim to inform the community and the health system so that they can work in a preventive way, providing an early diagnosis of patients and thus providing an appropriate management of the symptoms. We carried out an endpoint assay that indirectly quantifies NAGLU activity through the cleavage of 4-methylumbelliferone from the 4-methylumbelliferyl-2-acetamido-2-deoxy-α-D-glucopyranoside substrate. The activity of 463 healthy volunteers (Range: 0.6 - 4 nmol/mg/h, Median: 1.69 +/- 0.73) as well as 462 patients referred for clinical suspicion, was calculated. From the last group, 7 cases turned out to be positive (Range: 0 - 0.24 nmol/mg/h, Median: 0.13 +/- 0.09). The cut-off point according to ROC analysis between affected patients and controls was 0.42 nmol/mg/h. To our knowledge, this study is the first in Colombia where an estimated frequency of Sanfilippo type B is calculated by providing enzyme activity ranges and a cut-off point.
  • Differences in Newborn Screening Results Among Women with Gestational Diabetes Mellitus Original Article

    Estrella, Jane; Wiley, Veronica; Immanuel, Jincy; Simmons, David

    Abstract in English:

    Abstract Multiple studies undertaken on cord blood demonstrate analyte perturbations in infants exposed to gestational diabetes mellitus (GDM). Cord blood as a sample is influenced by maternal and placental metabolism. Newborn screening (NBS), performed after the first 24 hours of life reflects early neonatal metabolism. We compared NBS analytes between women with and without GDM with different management approaches in the Treatment of Booking of Gestational Diabetes (TOBOGM) pilot randomised controlled trial. Pregnant women with GDM risk factors were randomised to early or deferred GDM treatment following an oral glucose tolerance test (<20 weeks gestation). Women without GDM served as “decoys”. From the decoy group 11 developed GDM (screened at 26-28 weeks), were analysed separately; their results were compared with the other groups. De-identified controls were chosen from NBS results from the same analytic run matched for sex, birthweight and gestational age. Results were available for 73/78 women participating in the pilot and 358 de-identified controls. Tyrosine levels (μmol/l; whole blood)were higher in the late GDM group vs early, deferred treatment, and decoy groups (medians:106.28; IQR: 96.73-151.11) (76.33; 64.64-97.90) (75.68; 66.59-110.88)(73.74; 58.32-90.36) (p=0.009) and remained elevated when compared to normal, age-matched controls (106.28; 96.73-151.11) (87.26; 68.55-111.26) (p value=0.01) Immunoreactive trypsinogen (μgm/l; whole blood)was highest in the early treatment group when compared with group-specific controls (22.30; 13.90-29.90 vs 14.00, 10.60-21.10) (p=0.02). These results provide evidence of biochemical perturbations detectable on NBS of in-utero exposure to hyperglycemia and treatment and provide data for hypothesis building.
  • Clinical, Biochemical and Molecular Characterization of a Cohort of Glycogen Storage Disease Type I Patients in a High Complexity Hospital in Argentina Original Article

    Bindi, Verónica; Eiroa, Hernán D.; Crespo, Carolina; Martinez, María; Bay, Luisa

    Abstract in English:

    Abstract Glycogen storage disease type I is an autosomal recessive disorder of carbohydrate metabolism that manifests mainly by hepatomegaly and hypoglycemia with short fasts. Despite strict therapy, patients present long-term renal and liver complications. Data of 36 patients,29 GSD Ia and 7 Ib from a high complexity Hospital in Argentina was collected retrospectively. Collected data included diagnosis, anthropometric, biochemical parameters, therapy and follow-up. Treatment increased Height SDS (p=0.012). Patients with good adherence to therapy presented better growth parameters (p=0.049). Instead, admissions were detrimental (p =0.031) and were more common in Ib patients (p=0.002). The early appearance of complications (liver adenomas and nephropathy) was related to sustained triglyceride values > 500mg / dl (p=0.009 and 0.046 respectively). With intensive dietary treatment, clinical and biochemical status improves but cannot be completely corrected in most patients. Growth improves with treatment and this is optimized with adequate adherence. We must take into account that with ageing, more complications will develop.
  • “Atypical” Phenotypes of Neuronal Ceroid Lipofuscinosis: The Argentine Experience in the Genomic Era Original Article

    Pesaola, Favio; Guelbert, Guillermo; Venier, Ana Clara; Cismondi, Inés Adriana; Becerra, Adriana; Vazquez, Juan Carlos G.; Fernandez, Elmer; De Paul, Ana Lucia; Guelbert, Norberto; Noher, Inés

    Abstract in English:

    ABSTRACT Neuronal Ceroid Lipofuscinosis (NCL) refers to a group of inherited lysosomal storage disorders characterized by the intracellular accumulation of ceroid-lipofuscin compounds and neurodegeneration. Fourteen genes are currently recognized with disease-causing DNA variants: PPT1/CLN1, TPP1/CLN2, CLN3, DNAJC5/CLN4, CLN5, CLN6, MFSD8/CLN7, CLN8, CTSD/CN10, GRN/CLN11, ATP13A2/CLN12, CTSF/CLN13, KCTD7/CLN14, TBCK/CLN15. In the frame of the Cordoba cohort, we studied N=51 cases. The aim of this paper is the observational and retrospective analysis of the “atypical” phenotypes. PCR-Sanger sequencing and/or massive exome sequencing were used as a screening methodology. One CLN1 subject showed an atypical prolonged (P) phenotype with null PPT1 activity and a heterozygous compound genotype: E5 c.451C>T, p.Arg151*/g.6302T>G (I3 c.363-3T>G). Other 11 CLN2 individuals (except one girl) showed TPP1 activity decreased to around 10% of the minimum value of the reference interval in leukocytes and saliva. The DNA variants E7 c.827A>T, p.Asp276Val and I7 c.887-10A>G were the most prevalent. One CLN8 individual showed an atypical congenital phenotype with a heterozygous combination of DNA variants: E2 c.1A>G, p.?/E3 c.792C>G, p.Asn264Lys. Massive sequencing was installed as a screening methodology for the precision diagnosis of atypical CLN1, CLN2, and CLN8 phenotypes. A genetic/phenotypic local registry is under construction.
  • Review and Proposal of Alternative Technologies for Comprehensive and Reliable Newborn Screening Using Paper Borne Urine Samples for Lysosomal Storage Disorders: Glycosphingolipid Disorders Original Article

    Alonso-Fernández, José Ramón; López, Javier Fidalgo

    Abstract in English:

    Abstract Few current methods are efficient to detect a high number of lysosomal storage disorders (LSDs) in newborn screening. Therefore, we propose a stepwise procedure that starts with the use of paper borne urine samples (Berry-Woolf specimen) for the inexpensive detection of elevated lysosomal content and the identification of which of the three majors biochemical groups -mucopolysaccharides, oligosaccharides, and glycosphingolipids- is detected. Urine samples are preferable to blood samples because of their higher concentrations of the relevant analytes. Subsequent steps would precisely determine which enzyme deficiency is involved. As a summary, following our previous papers on the detection of elevated oligosaccharides and mucopolysaccharides, here we describe how elevated urinary glycosphingolipids (GSLs) could be fluorometrically detected using the reagent 5-hydroxy-1-tetralone (HOT) and subsequently identified with precision by continuous thin layer chromatography or other techniques. We also outline the steps required for the validation of this procedure for its introduction in newborn screening programs.
  • Quantitative Determination of Branched-Chain Amino Acids in Dried Blood Spot Samples by LC-MSMS and its Application in Diagnosis and Follow-Up of Chilean Patients with Maple Syrup Urine Disease Original Article

    Fuenzalida, K.; Valiente, A.; Faundez, A.; Guerrero, P.; Soto, V.; Leal-Witt, M.J.; Cabello, J.F.; Cornejo, V.

    Abstract in English:

    Abstract Elevation of branched-chain amino acids (BCAAs) in biological fluids indicates a deficiency in the branched-chain ketoacid dehydrogenase complex, which causes maple syrup urine disease (MSUD). Detection of increased levels of alloisoleucine confirms the diagnosis, while routine monitoring of leucine concentration is crucial for preventing metabolic decompensation and neurological dysfunction. In the metabolic center at Universidad de Chile, we have confirmed and monitored more than fifty MSUD patients in the last 20 years. Most diagnoses were made by clinical and sibling diagnosis, as MSUD is not included in the Chilean national newborn screening program. Shortening diagnosis time has a fundamental impact on the outcome of patients, therefore we focused on implementing detection of BCAAs in dried blood spot by liquid chromatography mass spectrometry (LC-MSMS) for disease confirmation as well as for biochemical monitoring. Retrospective analysis of samples from 9 diagnosed MSUD patients were performed; BCAAs values were determined via MSMS and LC-MSMS conducted in parallel. Leucine and alloisoleucine levels were positively correlated with patient’s diagnosis age. Alloisoleucine was significatively elevated as early as 24 hr after birth. A predictable variation in BCAAs levels after nutritional intervention among diagnosed MSUD patients was found.
  • Update on Dietary Compliance, Nutritional Status, and Neuropsychological Functioning in the Chilean Phenylketonuria cohort Original Article

    Leal-Witt, M.J.; Salazar, M.F.; Peñaloza, F.; Castro, G.; Hamilton, V.; Arias, C.; Peredo, P.; Valiente, A.; De la Parra, A.; Cabello, J.F.; Cornejo, V.

    Abstract in English:

    Abstract Since 1992, Chile has had a Newborn Screening Program for Phenylketonuria (PKU), which currently has an incidence of 1:18,916 newborns. The objective of the current study was to describe the 2020 follow up of the Chilean PKU cohort. The variables analyzed were: nutritional status, dietary compliance and neuropsychological functioning. We conducted a descriptive cross-sectional statistical analysis. The 271 subjects with PKU had an average age of diagnosis of 17±8 days and a phenylalanine (Phe) level of 1122±546 umol/L. Approximately 80% of protein requirement came from a protein substitute. For those <18 years of age, 80% had good dietary compliance with Phe level between 120-360 umol/L and those >18 years had a median of 522 umol/L (95%CI 468 - 636). Forty-four percent of the active PKU cohort had overweight/obesity. Eighty-five percent of the cohort >4 years of age had a normal intelligence quotient (IQ) (score 80-120). We observed a negative correlation (p <0.001; 95% CI: - 0.5, -0.2) between IQ score and Phe level. The Chilean protocol and protein substitute subsidy for life, together with the follow-up and continuous education carried out by the clinical team has encouraged compliance.
  • Amino Acids and Acylcarnitines Reference Values for Neonatal Screening of Inborn Errors of Metabolism in Colombia by Tandem Mass Spectrometry Original Article

    Bermúdez, Antonio; Robayo, Dora; Porras, Gloria; Acosta, María Amparo

    Abstract in English:

    Abstract Neonatal screening in Colombia has been carried out since 2000. The problem that most concerns is the absence of expanded screening. To stablish reference values for amino acids and acylcarnitines, in order to provide information to guide the implementation of expanded screening. Samples collected on Whatman 903 filter paper from 10284 newborns were processed by Tandem Mass Spectrometry System (Waters - Perkin Elmer), and the NeoBase™ non-derivatized MS/MS kit (PerkinElmer), which contains controls for 11 amino acids, and 31 acylcarnitine species. For each analyte the upper limit was set above the 99th percentile, while the lower limit was set below the 1st percentile. Comparison of full-term newborn amino acid concentrations with premature ones showed no significant differences in three of them: Glycine p-0.99574, Ornithine p=0.35274, Phenylalanine p=0.13499, neither in levels of 11 of the 31 acylcarnitines. Comparison of analyte concentrations in this study with previous reports showed significant differences for all amino acids and acylcarnitines (<0.05). Experience was gained in the pre-analytic stage of expanded screening and reference values were established, for the implementation of neonatal screening program in the country.
  • Molecular Characterization of the GBA Gene in Patients from Southwest of Colombia with Gaucher Disease Original Article

    Terranova, Daniela Arturo; Giraldo, Lina Johanna Moreno; Idrobo, Henry; Satizabal, José María

    Abstract in English:

    Abstract Introduction Gaucher's disease (GD) is an autosomal-recessive lysosomal storage disorder that results from hereditary deficiency of the acid glucocerebrosidase enzyme, encoded by the GBA gene necessary for the degradation of glucosylceramide. Objective molecularly characterize the variants found in the GBA gene present in patients from the Southwest of Colombia with GD. Material and methods 19 patients were included in the study, clinically and enzymatically diagnosed with GD. A molecular analysis of the GBA gene was performed and the variants were subsequently searched in different population and clinical databases. A bioinformatic analysis was performed. Results The variants in the GBA gene reported were classified into: 14/19 homozygous patients, 4/19 compound heterozygote and 1/19 heterozygous. The presence of 7 variants coding for 8 different genotypes was reported. Also the known mutations like Asn409Ser, p.Leu483Pro, p.Lys237Glu, p.Glu427Lys, and p.Arg535His were identified in these patients. The most frequent genotype was p. Asn409Ser / Asn409Ser (36%). All the variants presented a pathogenic clinical significance. Conclusion The given study will make it possible to understand the susceptibility to GD in the population. This can help maintain the health quotient of the population through premarital counseling and therefore minimize the burden of disease among the population.
  • Twenty Years of Neonatal Screening for Sickle Cell Disease in Brazil: The Challenges of a Continental Country with High Genetic Heterogeneity Original Article

    Santos, Helena Pimentel dos; Domingos, Claudia Regina Bonini; Castro, Simone Martins de

    Abstract in English:

    Abstract Sickle cell disease (SCD) is the most common inherited hematological disease worldwide. The benefits of diagnosis and early intervention have led to the wide dissemination of public health programs worldwide. Through neonatal screening programs, it is possible to reduce morbidity and mortality in the first 5 years of life. The prophylactic use of penicillin, the anti-pneumococcal vaccine and other intensive care, increase the survival and quality of life of people with SCD. The aim of this study is to present the 20-year history of screening for hemoglobinopathies in Brazil and its challenges. From 2001 to 2019, an average of 2,400,000 children were screened per year nationwide, with the coverage being of 82,16%. The screening of 54,9% of newborns is collected up to their 5th day of life. The prevalence of SCD was 1:2,263 newborns; therefore, it was the second most-common disease detected by the program of Brazil, being only after hypothyroidism (1/2,175 live births). The healthcare system should provide the necessary infrastructure to confirm the diagnosis of newborns and to provide appropriate counseling and treatment. The early diagnosis and treatment, as well as the follow-up with a multidisciplinary team, are fundamental to the survival rate and the quality of life of patients.
  • 25 Years of Newborn Screening in Uruguay Original Article

    Queijo, Cecilia; Lemes, A.; Queiruga, G.

    Abstract in English:

    Abstract In the 1960s Guthrie conceived the idea of preventing congenital disease using dried blood spot samples on filter paper to detect them through biochemical tests and then be able to treat environmental factors in time to avoid the devastating effect of the diseases. Uruguay started in 1994 with the detection of congenital hypothyroidism in umbilical cord blood. In 2007 it was extended to Phenylketonuria and Congenital Adrenal Hyperplasia, starting with dried blood spot sample. In 2008, with the incorporation of Mass Spectrometry, a pilot program was started for the detection of aminoacidopathies, beta-oxidation defects and organic acidemias disorders. In the following years, the program expanded to more diseases, reaching a total of 25 disorders that could be detected, 5 of them are investigated on a mandatory basis and others in pilot program. During the 25-year of experience, 974277 umbilical cord blood samples were analyzed and since 2007: 532684 dried blood spot samples. 613 true positive congenital disorders were identified. The coverage has been greater than 98% and the repetition rate for insufficient samples less than 1.9%.
  • Patient-Reported Outcomes in Subjects With A143T and R118C GLA Gene Variants Original Article

    Rosa Neto, Nilton Salles; Bento, Judith Campos de Barros; Pereira, Rosa Maria Rodrigues

    Abstract in English:

    Abstract Background Fabry disease (FD) is caused by pathogenic variants in the GLA gene. A143T and R118C variants are considered not disease causing. Patient-reported outcomes provide information concerning the effects of their disease but should be carefully analyzed in rare diseases. Objectives To evaluate pain, depression, sleep disturbances, disability and quality of life in A143T or R118C Brazilian subjects and compare to data published for classic FD patients. Methods Nineteen subjects - 8:11 male:female - were evaluated and answered the questionnaires: Brief Pain Inventory (BPI), Hamilton Depression Rating Scale, Pittsburgh Sleep Quality Index, Health Assessment Questionnaire Disability Index (HAQ-DI), Short-Form Health Survey 36 (SF-36). Lyso-Gb3 and residual enzyme activity were obtained. Results Alpha-galactosidase A activity was low in males. Lyso-Gb3 levels were normal in all subjects. Comparing A143T/R118C subjects and FD patients, BPI severity, BPI interference, HAQ-DI values were not different (p>0.05) whereas raw scores for physical functioning (p=0.01) and general health perception (p<0.01) favored A143T/R118C. Depression and sleep disturbances were similar between groups. Conclusions A143T/R188C subjects had normal lyso-Gb3 levels. Depression, sleep disturbances and disability were frequent and under-recognized. However, findings depicted in this study are nonspecific and should not be considered as ground for diagnosing Fabry disease.
  • How Long are Residual Newborn Screening Specimens Useful for Retesting when Stored in Suboptimal and Uncontrolled Conditions of Temperature and Humidity? Original Article

    Borrajo, Gustavo J.C.; Doña, Vanina V.

    Abstract in English:

    Abstract Residual DBS specimens from newborns diagnosed with Phenylketonuria, Congenital Hypothyroidism, Cystic Fibrosis, Congenital Adrenal Hyperplasia and Galactosemia collected within 1995-2018, stored in cardboard boxes at ambient temperature in uncontrolled conditions, were retested for phenylalanine (Phe), thyrotropin (TSH), immunoreactive trypsinogen (IRT), total galactose (TGal) and 17-hydroxyprogesterone (17OHP), to demonstrate how long are they stable in these conditions and useful to reconfirm a previous abnormal result. Recovery percentage at retesting and qualitative interpretation regarding the current cutoff were evaluated. Phe, TSH and IRT recoveries showed decreasing trends along time. Phe recovery was 64 % after 2-years storage; TSH decayed rapidly recovering 47.3 % at 1-year, while IRT showed recoveries of 60 % at 1-year. Although 17OHP recovery presented a wide variation of results, a decaying trend was also found. Results suggest 17OHP is more stable than TSH and IRT, as supported by recoveries > 71 % when stored ≤ 2-years. TGal recovery presented an erratic behavior, so that it was not possible to estimate expected concentrations as a function of storage time. TGal recoveries above 100 % were found in UDP-galactose-4-epimerase and galactose-1-phosphate uridyltransferase deficiencies, evidencing possible galactose liberation from other sources. These results make a very valuable contribution for programs storing residual DBS in uncontrolled conditions.
  • Spatial Distribution of Congenital Disorders Diagnosed by the Newborn Screening Program in Ecuador Original Article

    Pozo-Palacios, Juan; García-Díaz, Génesis; Cruz, Fernando; Porras, Fabián; Heras, Jessica; Cano-Pérez, Eder

    Abstract in English:

    Abstract The newborn screening program in Ecuador has been operating since 2011 under the responsibility of the Ministry of Health. This program is centralized and diagnoses four diseases: congenital hypothyroidism, phenylketonuria, galactosemia, and congenital adrenal hyperplasia. This study aimed to assess the geographical distribution of newborn screening cases in Ecuador. Spatial analysis techniques were applied using the records of the National Newborn Screening Program with a congenital disease confirmed from January 2012 to December 2019. Morbidity rates per 100,000 were calculated by newborn screening disease detected and the province of birth, posteriorly, the map of its distribution was graphed and assessed using the QGIS 3.12 software. In total, 393 cases born confirmed between 2012 and 2019 were registered. The distribution of every disease tends to be different in all provinces in Ecuador; the spatial variation was significant and relative rates showed a higher incidence in some eastern provinces. In conclusion, we found a different distribution and rates of newborn screening disorders in Ecuador. The high incidence of congenital hypothyroidism, phenylketonuria, galactosemia, and congenital adrenal hyperplasia in some areas should be investigated, due could be related to ethnic, genetic, and cultural aspects of the population.
  • Clinical and Nutritional Evolution of 24 Patients with Glutaric Aciduria Type 1 in Follow-up at a Center Specialized in Inborn Errors of Metabolism in Chile Original Article

    Arias, Carolina; Hidalgo, Isabel; Salazar, María Florencia; Cabello, Juan Francisco; Peñaloza, Felipe; Peredo, Pilar; Valiente, Alf; Fuenzalid, Karen; Guerrero, Patricio; Cornej, Verónica

    Abstract in English:

    Abstract Introduction: Glutaric Aciduria Type 1 (GA-1) is produced by the enzymatic deficiency of glutaryl-CoA-dehydrogenase (GCDH), leading to the accumulation of glutaric acid (GA). 90% of patients without early treatment present acute encephalopathic crisis (AEC), followed by disabling neurological symptoms. The treatment consists of a low lysine (Lys) diet, protein substitute lys-free, tryptophan-reduced (PS) and L-carnitine. Objectives: Describe the clinical and nutritional evolution of a cohort of GA-1 patients at a national referral center in Chile. Methodology: Retrospective study of 24 patients diagnosed with GA-1 between 1998-2020 and referred to the Institute of Nutrition and Food Technology (INTA) of University of Chile. Results: Age at diagnosis was 19±27 months; 10/24 presented AEC and neurological sequelae. The cases without AEC (14/24) 8 presented neurological compromise: psychomotor development delay, abnormal movements and pyramidal syndrome. Nutritional evaluation: 12/24 were malnourished by deficiency, <6 years old group (12/24): 11 cases were found to have Lys and PS, ≥6 years old (12/24): 9/12 did not receive PS. All had normal free carnitine levels. Conclusion: GA-1 has variable symptoms with neurological involvement AEC or insidious start. Is essential to maintain a long-term follow-up and consider its inclusion in neonatal screening programs.
  • Clinical and Genetic Characterization and Biochemical Correlation at Presentation in 48 Patients Diagnosed with Urea Cycle Disorders at the Hospital Juan P Garrahan, Argentina Original Article

    Bernal, Ana Clara; Tubio, Maria Cruz; Crespo, Carolina; Eiroa, Hernán Diego

    Abstract in English:

    Abstract The clinical and biochemical findings in a cohort of 51 patients with urea cycle disorders followed at the Hospital Garrahan, Buenos Aires, Argentina were analyzed at the time of diagnosis (3 female patients were excluded). Of this cohort, 13/48 patients had early-onset (EO), 23/48 had late-onset (LO), and 12/48 had a different presentation because they had a family risk background (FRB) and had been diagnosed since they were born. The most frequent deficiency disorder was OTCD (65%). The initial ammonium value was evaluated, being higher in the EO group, with a statistically significant difference when compared with LO and FRB. 15/48 patients fell into a coma at the time of diagnosis, mean ammonia was 829.54 μmol / L, and 33/48 did not fell into a coma, the mean ammonium was of 159.3 μmol / L (p = 0.001). 15 patients died: 62% EO, 22% LO (p=0.0216), 17% FRB. A molecular study was performed on 35 patients. Patients with EO presentation suffer the most severe forms and still have high morbimortality. On the other hand, LO forms are forms of less severity that are finally diagnosed as a result of one or more acute episodes.
  • 25 Hydroxy Vitamin D Level, Bone Health, Vitamin D and Calcium Intake in Chilean Patients with Phenylketonuria and Hyperphenylalaninemias Original Article

    Leiva, C.; Bravo, P.; Arias, C.; Cabello, J.F.; Leal-Witt, M.J.; Salazar, F.; Cornejo, V.

    Abstract in English:

    Abstract It has been shown that there is a decrease in the concentrations of 25 hydroxyvitamin D (25-OHD) and bone mineral density (BMD) in patients with phenylketonuria (PKU) in their follow-up. Our objective was to determine concentrations of 25-OHD in subjects with PKU and hyperphenylalaninemia (HPA). Transversal analytical study considered three groups: G1-PKU with neonatal diagnosis and formula intake without Phe; G2-HPA, without specific treatment and G3-C control group. Sixteen patients per group (aged 6-23) were included. Levels of 25-OHD, lumbar spine (L2-L4), femur and total BMD, intact parathormone (PTH) and vitamin D (VitD) and calcium intake were calculated. The Kruskal-Wallis statistical test was applied (p-value<0,05). Significant differences were detected in concentrations of 25-OHD between G1-PKU and G2-HPA (38.9 ng/mL; 28 ng/mL, respectively) (NV: >30 ng/mL). G1-PKU had a higher intake of VitD, with differences among groups. There were no significant differences among groups in relation to BMD and intact PTH. In conclusion, G1-PKU under treatment and with good adherence, does not present VitD deficiency and no BMD alterations are observed. In contrast, G2-HPA had a lower intake of VitD and decreased 25-OHD concentrations which could affect the bone architecture in the long term. Further studies on the G2-HPA are suggested.
  • Determination of the Population Allelic Frequency of the Variants of the MPS Complex in Southwestern Colombia Original Article

    Giraldo, Lina Johanna Moreno; Satizabal, José María; Gómez, Adalberto Sánchez

    Abstract in English:

    Abstract Mucopolysaccharidoses are lysosomal storage diseases characterized by the excessive accumulation of glycosaminoglycan sulfate in organs and tissues. To determine the population allelic frequency of the MPS complex variants in a population without clinical and molecular diagnosis of MPS. An observational descriptive study was carried out where the allelic frequency of variants presents in the IDUA, IDS, SGSH, NAGLU, HGSNAT, GNS, GALNS, GLB1, ARSB, GUSB, HYAL1 genes was determined by means of the sequencing of 320 exomes from patients without a clinical diagnosis of MPS; the results were tabulated, and allelic frequency formulas were used to determine the values associated with each of the genes. 509 alleles associated with the MPS complex were reported, of which 262 have not been previously reported. Genes with the most frequent allelic presence were IDUA, GLB1 and GALNS, involved in MPS I and MPS IV A / B. The total frequencies ranged between 0.00393 (2 alleles) and 0.47937 (248 alleles). These studies make it possible to determine polymorphisms that circulate in the country, present in patients not affected with MPS, allowing to expand the knowledge about the characteristics of the alleles that are present in affected patients.
  • Platelet Membrane Glycoprofiling in a PMM2-CDG Patient Original Article

    Papazoglu, G.M.; Ruiz, S.M. Silvera; Salinas, R.; Pereira, M.I.; Cubilla, M.A.; Pesaola, F.; Ghione, S.; Ramadán, N.; Martinez-Duncker, I.; Asteggiano, C.G.

    Abstract in English:

    Abstract Congenital disorders of glycosylation (CDG) are metabolic hereditary diseases caused by defects in the synthesis of glycoconjugates. CDG have been described in sugar-nucleotide biosynthesis and transporter, glycosyltransferases, vesicular transport, as well as in lipid biosynthesis and glycosylphosphatidylinositol anchors. PMM2-CDG is caused by mutations in the phosphomannomutase-2 (PMM2) gene and shows autosomal recessive inheritance. It affects all organs and tissues, ranging from severe psychomotor retardation to moderate intellectual disability. Alterations in the primary haemostatic system have been reported in these patients and they can lead to severe bleeding or excessive thrombosis with subsequent vascular insufficiency. Despite of being the most common CDG, platelet glycosylation and sialylation defects in PMM2-CDG patients remain incompletely characterized. In this study, we applied a lectin-based flow cytometry approach to report the first characterization of the highly glycosylated platelet membrane glycan profile in a PMM2-CDG patient. In the PMM2-CDG patient’s platelet samples, a decreased binding of SNA lectin, indicative of reduced terminal α-2-6 sialic acid content, and an increased binding of PNA lectin, suggesting desialylation of β-1-N-acetylgalactosamine residues, were observed. Reduced expression of terminal sialic acids in platelet membrane glycoproteins may contribute to the increased risk of hemorrhage reported in these patients by promoting platelet clearance and thrombocytopenia.
  • Consolidation of the Neonatal Screening Program as a Public Health Program in Paraguay Original Article

    Ascurra, Marta; Alvarez, Pamela; Ortíz-Paranza, Lourdes; Blanco, Fabiola; Valenzuela, Adriana; Insaurralde, Anahi; Rodríguez, Stella; Salinas, Mirna; Porzio, Giovanna; Núñez, Andrea

    Abstract in English:

    Abstract In Paraguay, neonatal screening for congenital hypothyroidism (CH) and phenylketonuria (PKU) started in October 1999, in 2005 cystic fibrosis (CF) was selectively incorporated. The National Program for Neonatal Screening has a centralized laboratory that encompasses 1.132 Sample Collecting Sites (SCS) distributed in the 18 Health Regions, with over 80% coverage of live births; the incidence of CH being 1:2.060, HPA/PKU 1:6.328 and CF 1:5.671 newborns. The newborn screening program headed by the Ministry of Public Health and Social Welfare in Paraguay has been consolidated itself as a public health program. This publication describes the historic 20-year process, the strategies and activities carried out as well as the results and achievements, among which it is important to point out the achievement of newborns screening laws that make mandatory to detect, diagnose and treat those affected, as well as the human resources committed to newborn screening.
  • Bone Health in Adults with Phenylketonuria: A Cross-Sectional Study Original Article

    Aggarwal, Anjali; Northrup, Hope; Rodriguez-Buritica, David F.; Hashmi, S. Shahrukh; Saavedra, Heather

    Abstract in English:

    Abstract Available literature documenting BMD in patients with PKU is mostly reported among heterogeneous populations including adults and children. We aim to describe the bone health status among adults (aged >18 years) affected with Phenylketonuria (PKU) and to evaluate the effect of diet and exercise on bone mineral density (BMD). Sample size of the study population was 27. Enrolled patients underwent multi-site Dual-energy X-ray absorptiometry (DXA) scan and laboratory tests. Nutritional and physical activity records were obtained on each subject to ascertain bone health. BMD in patients with PKU was low normal. 14% of the study subjects were found to have osteoporosis in at least one measured skeletal site. 70% had low BMD in one or more of the measured skeletal sites. BMD score was lowest at radius. Moderate correlation was observed between femoral and radial BMD and serum calcium level. Dietary intake of vitamin A was moderately correlated with BMD T-scores in femur. Our results indicate that BMD in patients with PKU is low normal with better BMD with vitamin A intake, trend towards better bone health with physical exercise and Sapropterin intake.
  • Clinical Manifestation in Females with X-linked Metabolic Disorders: Genetic and Pathophysiological Considerations Review

    Beck, Michael

    Abstract in English:

    Abstract Inborn errors of metabolism are predominantly autosomal-recessive disorders, but several follow an X-linked pattern of inheritance. They are called X-linked recessive, if the female carriers are asymptomatic, and are called X-linked dominant disorders, if almost all females are affected. Conditions, in which some females have symptoms while others are asymptomatic lifelong are simply referred to as X-linked. The aim of this review is to point out the variability in clinical manifestation of affected females in some X-linked metabolic disorders and to discuss on the basis of these examples possible mechanisms that may explain the broad phenotypic spectrum, such as the type of the underlying mutation, the issue of autonomous versus non-autonomous gene expression and the degree of skewing of X-inactivation. The use of the terms “X-linked dominant” and “X-linked recessive” will be discussed.
  • A decade of molecular diagnosis of Mucolipidosis II and III in Brazil: a pooled analysis of 32 patients Review

    Ludwig, Nataniel F; Sperb-Ludwig, Fernanda; Randon, Dévora N; Bernardi, Pricila; Giuliani, Liane R; Moreno, Carolina A; Cavalcanti, Denise P; Silva, Luiz CS da; Schwartz, Ida V D

    Abstract in English:

    Abstract GlcNAc-1-phosphotransferase is a hexameric complex formed by subunits α, β, and γ, where the first two are encoded by the GNPTAB gene and the third by the GNPTG gene. Pathogenic variants identified in the GNPTAB gene cause the diseases Mucolipidosis II and III alpha/beta, which are severe and characterized by an overflow of lysosomal hydrolases into the extracellular environment, and their absence in lysosomal compartments causes an accumulation of non-degraded macromolecules. Methodology: a retrospective study that included 32 unrelated Brazilian patients with a clinical and genetic diagnosis of Mucolipidosis II/III alpha/beta. The regional frequency of the altered alleles was determined. Results: The patients were from all regions of Brazil. The most prevalent variants were c.3503_3504del, associated with the severe form of the disease, and c.1208T>C, associated with the milder form. Variant c.3503_3504del is the most frequently found in the Midwest, Northeast, and Southeast regions of Brazil. In the South, 42.8% of the alleles present the c.1196C>T variant. Conclusions: From the perspective of all patients diagnosed with Mucolipidosis II/III in Brazil, it is possible to conclude that different regions present allelic frequencies of specific pathogenic variants, which can be explained by the occurrence of a founding effect or high inbreeding rates.
  • Depression: The Hidden Problem in Fabry Disease. A Review Review

    Chertcoff, Anibal; Cejas, Luciana León; Marchesoni, Cintia; Reisin, Ricardo

    Abstract in English:

    Abstract Fabry disease (FD) is an X-linked disorder of glycosphingolipids caused by mutations of the GLA gene. The classical form presents with neuropathic pain and gastrointestinal complaints since childhood or adolescence and progressing into adulthood with ischemic stroke, cardiac dysfunction, and chronic kidney disease. Depression seems to be a frequent complication of FD but its frequently underdiagnosed and undertreated. Comorbid depression in different chronic diseases has been associated with an overall increase in disease burden and medical costs, impairment in activities of daily living, and impact on self-care and treatment adherence. In addition, a clear association between pain and depression has been observed in FD patients and appears to have an unequivocal neurobiological matrix. The aim of this review is to provide an overview of the literature on depression in patients with FD and to highlight some of the emerging issues on this topic. Further research to improve detection and to develop effective treatments for depression in this population is promptly needed.
  • Difficulties in the Diagnosis of Gaucher Disease in a Low-Income Country: A Case Report from Mozambique Short Communication

    Pinto, Félix; Nassone, Ema; Ismail, Muhammad; Jamisse, Astrilde; Kubaski, Francyne; Brusius-Facchin, Ana Carolina; Giugliani, Roberto; Madeira, Luís; Fernandes, Fabíola

    Abstract in English:

    Abstract Introduction: Gaucher disease (GD) is one of the common lysosomal storage disorder (LSD) with an estimated frequency of one in 40,000 newborns globally. GD is an autosomal recessive condition, which results from mutations in the GBA1 gene, causing partial or complete deficiency of β-glucocerebrosidase enzyme activity, which leads to the widespread accumulation of the substrate glucosylceramide. Aims: This report presents different challenges of clinical management and communication between medical specialties to reach diagnose of any rare disease in Mozambique, a low-income country, which health system has limited infrastructure, trained personnel, and budget for diagnosis and to provide treatment for rare genetic disorders such as GD. Case Presentation: The patient was a 15-year old black female patient of Mozambican nationality born from non-consanguineous parents. Three of the four patient’s siblings were healthy; one sister had died of a disease with a similar clinical features. Our patient presented with abdominal distention and hepatosplenomegaly. Blood tests revealed pancytopenia and a high level of ferritin. Liver biopsy and histologic examination revealed infiltration of the splenic parenchyma and portal area of the liver as well as enlarged histiocytic cells with granular cytoplasm. Magnetic resonance imaging showed liver enlargement, changes in the femoral heads without osteonecrosis, a pathological fracture of the third thoracic vertebrae (T3), with absence of brain and spinal cord neurological abnormalities. The biochemical investigation disclosed low levels of β-glucocerebrosidase (0.223 nmol/h/ml; normal: above 0.98) and increased levels of lyso-Gb1 (0.43 µg/ml; normal: up to 0.003). Genotyping of the GBA1 gene indicated the presence of the pathogenic variant p.Arg87Trp (R48W) in homozygosis. Discussion and Conclusion: To the best of our knowledge, this report describes the first case of GD type 1 confirmed via biochemical and molecular genetic testing in Mozambique. As awareness of the GD and rare genetic diseases among Mozambican health professionals is very limited, and resources for diagnosis are scarce in the national health system, it is possible that other cases remain undiagnosed in this low-income country.
  • Inherited Metabolic Diseases as a Multisystem Model of Mental Disorders Research Short Communication

    Rukavishnikov, Grigory; Kasyanov, Evgeny; Zhilyaeva, Tatiana; Neznanov, Nikolay; Mazo, Galina

    Abstract in English:

    Abstract Recent biological and genetic research data confirm shared pathological mechanisms of inherited metabolic diseases and mental disorders. We suggest that for further research a model of synergistic heterozygosity can become a convenient tool. In that case the use of inherited metabolic disorders as a multisystem research model can provide both significant theoretical and practical results. At the initial stage of this hypothesis evaluation, it seems efficient to screen for mental symptoms the families of patients with inherited metabolic disorders.
  • Clinical and Radiological Characterisation of Patients with Mucopolysaccharidosis in a Genetic Clinic Short Communication

    Swetha, Pallavelangini; Panigrahi, Inusha; Saxena, Akshay; Kaur, Anupriya; Thakur, Rozy

    Abstract in English:

    Abstract The mucopolysaccharidoses (MPS) are a relatively uncommon group of inherited metabolic disorders. MPSs should be suspected in a child with coarse facies, organomegaly, recurrent respiratory tract infections, developmental delay, and hernias. Early diagnosis and treatment can greatly improve the quality of life in these children. In this study we studied 46 MPS patients diagnosed on enzyme and/or DNA testing and we found that the MPS II was the most common type followed by MPS I and MPS IVA. While the mean age of onset of symptoms was 12 months, the mean age at diagnosis was 4.5 years, a significant delay. One of major presenting features was recurrent respiratory problems, more prevalent in MPS II cases. Many patients also had short stature and contractures. Increasing awareness among physicians is of paramount importance for the early diagnosis and optimal treatment and prevention by prenatal testing and counselling.
  • Importance of Studying Older Siblings of Patients Identified by Newborn Screening: a Single-Center Experience in Mexico Short Communication

    Ibarra-González, Isabel; Fernández-Lainez, Cynthia; Guillén-López, Sara; López-Mejía, Lizbeth; Belmont-Martínez, Leticia; Nieto-Carrillo, Rosa Itzel; Vela-Amieva, Marcela

    Abstract in English:

    Abstract Introduction: Any abnormal newborn screening (NBS) test should be subjected to appropriate diagnostic tests and should be followed. Once the newborn has been diagnosed and treated, the family should receive comprehensive genetic services. Aim: To present the experience of studying older siblings of patients with inborn errors of metabolism (IEM) identified by NBS in a single-national follow-up reference center. Methods: A retrospective analysis of medical files of the IEM patients detected by NBS was conducted. All those older siblings who tested positive for the same IEM of the patient detected by newborn screening were included. Results: A total of 26 positive siblings from 18 families with seven different IEM were found (phenylketonuria, argininemia, glucose-6-phosphate dehydrogenase deficiency, 3-methylcrotonyl-CoA carboxylase deficiency, dihydropteridine reductase deficiency, tyrosinemia type 3, and medium chain acyl-CoA dehydrogenase deficiency). The age range of the affected siblings was 2 to 19 years old, with a mean age of 8.5 years. Ten older siblings (38.5%) had clinical consequences for the disease, including severe intellectual disability. Conclusions: It is necessary to study older siblings, and family history and genetic counseling of all NBS-detected families should be recommended, especially in countries where expanded NBS programs are beginning.
  • A Novel Mutation (p.Met1?) of a Cuban Patient in the NAGLU Gene with Mucopolysaccharidosis IIIB Short Communication

    Rey, Laritza Martínez; Sánchez, Tatiana Acosta; Naranjo, Deynis Carmenate; Cuesta, Hector Vera

    Abstract in English:

    Abstract Mucopolysaccharidosis III (MPSIII) or Sanfilippo syndrome is an autosomal recessive disorder of lysosomal metabolism. MPS III is caused by mutations in genes that encode for the enzymes involved in the degradation of heparan sulfate. It is classified into 4 subtypes (MPSIII A-D). MPS IIIB is induced by mutations in the gene encoding the alpha-N-acetylglucosaminidase enzyme. We report a 6-year-old boy with phenotypic findings of Sanfilippo syndrome type B, such as mild coarse facie, clear corneas, hirsutism, hepatomegaly, mild joint stiffness and mild dysostosis multiplex. He also presents frequent upper respiratory infections, bilateral hearing loss, sleep disturbances, progressive neurologic deterioration and behavioral problems. He is compound heterozygous for the NAGLU gene (c.503G˃A; p.Trp168Ter/ c.3G˃A; p.met1?). One of the mutation was described in two patients before. A novel pathogenic variant was detected.
Latin American Society Inborn Errors and Neonatal Screening (SLEIMPN); Instituto Genética para Todos (IGPT) Rua Ramiro Barcelos, 2350, CEP: 90035-903, Porto Alegre, RS - Brasil, Tel.: 55-51-3359-6338, Fax: 55-51-3359-8010 - Porto Alegre - RS - Brazil
E-mail: rgiugliani@hcpa.edu.br