Resumo em Inglês:

Abstract GM1 gangliosidosis is a rare autosomal recessive lysosomal storage disorder with high prevalence in Brazil (1:17 000). In the present study, we genotyped 10 individuals of 9 unrelated families from the States of São Paulo and Minas Gerais diagnosed with the juvenile and chronic forms of the disease. We found the previously described p.Thr500Ala mutation in 8 alleles; c.1622-1627insG and p.Arg59His in 2 alleles (the latter also segregating with c.1233+8T>C); and p.Phe107Leu, p.Leu173Pro, p.Arg201His, and p.Gly311Arg in 1 allele each. Two mutations (p.Ile354Ser and p.Thr384Ser) and 1 neutral alteration (p.Pro152=) are described for the first time. All patients presented as compound heterozygotes. A discussion on genotype–phenotype correlation is also presented.

Resumo em Inglês:

Abstract The ADHD Rating Scale (ADHD RS-IV; parent report) and Adult ADHD Self-Rating Scale (ASRS; self-report) are validated instruments for measuring symptoms of attention-deficit/hyperactivity disorder (ADHD). The objectives of this study were to elicit descriptions of phenylketonuria (PKU) symptoms and assess content validity of these instruments in PKU. Parents (N = 15) of children with PKU (?8 years old) and adults with PKU (N=13) described PKU-related symptoms and commented on the scale’s clarity, comprehensiveness, and relevance to their experience with PKU. Most of the adults (84.6%) and all of the children were on a phenylalanine-restricted diet, according to respondent report. The inattentiveness symptoms reported by participants mapped to the inattentive items of the questionnaires. Most participants felt the inattentive items were clear and relevant to their experience. Despite study design limitations, these results demonstrate the relevance of assessing inattentiveness in PKU, and both instruments achieved content validity for inattentive subscale items.

Resumo em Inglês:

Abstract Newborn screening for the detection of inborn errors of metabolism (IEM), endocrinopathies, hemoglobinopathies, and other disorders is a public health initiative aimed at identifying specific diseases in a timely manner. Mexico initiated newborn screening in 1973, but the national incidence of this group of diseases is unknown or uncertain due to the lack of large sample sizes of expanded newborn screening (ENS) programs and lack of related publications. The incidence of a specific group of IEM, endocrinopathies, hemoglobinopathies, and other disorders in newborns was obtained from a Mexican hospital. These newborns were part of a comprehensive ENS program at Ginequito (a private hospital in Mexico), from January 2012 to August 2014. The retrospective study included the examination of 10 000 newborns’ results obtained from the ENS program (comprising the possible detection of more than 50 screened disorders). The findings were the following: 34 newborns were confirmed with an IEM, endocrinopathies, hemoglobinopathies, or other disorders and 68 were identified as carriers. Consequently, the estimated global incidence for those disorders was 3.4 in 1000 newborns; and the carrier prevalence was 6.8 in 1000. Moreover, a 0.04% false-positive rate was unveiled as soon as diagnostic testing revealed negative results. The most frequent diagnosis was glucose-6-phosphate dehydrogenase deficiency; and in the case of carriers, it was hemoglobinopathies. The benefit of the ENS is clear as it offers prompt treatment on the basis of an early diagnosis including proper genetic counseling. Furthermore, these results provide a good estimation of the frequencies of different forms of newborn IEM, endocrinopathies, hemoglobinopathies, and other disorders at Ginequito.

Resumo em Inglês:

Abstract Glycogen storage disease type 1a (GSD 1a) is a rare inborn error of metabolism. It causes severe fasting intolerance and lactic acidosis due to the deficiency of glucose-6-phosphatase enzyme. Blood glucose and lactate concentrations from 2 patients with GSD 1a were retrospectively compared to a control group of patients with familial amyloid polyneuropathy. Carbohydrate intake and infusions were compared to experimental data based on stable isotope studies. Perioperative lactate concentrations were significantly higher in our 2 patients with GSD 1a (median 15.0 mmol/L; range 9.9-22.0 mmol/L) versus 8 controls. In one patient, despite normal blood glucose concentrations, lactate acidosis was probably caused by a combination of the disease itself, insufficient (par)enteral carbohydrate intake, Ringer lactate infusions, and circulatory insufficiency. Patients with GSD 1a carry an increased risk of lactic acidosis during orthotopic liver transplantation compared to non-GSD patients. Multidisciplinary perioperative care is essential to prevent significant complications.

Resumo em Inglês:

Abstract Succinyl-CoA:3-oxoacid CoA transferase (SCOT) deficiency is an autosomal recessive disorder of ketone body utilization that is clinically characterized with intermittent ketoacidosis crises. We report here the second Turkish case with SCOT deficiency. She experienced 3 ketoacidotic episodes: The first ketoacidotic crisis mimicked diabetic ketoacidosis because of the associated hyperglycemia. Among patients with SCOT deficiency, the blood glucose levels at the first crises were variable, and this case had the highest ever reported blood glucose level. She is a compound heterozygote with 2 novel mutations, c.517A>G (K173E) and c.1543A>G (M515V), in exons 5 and 17 of the OXCT1 gene, respectively. In patient’s fibroblasts, SCOT activity was deficient and, by immunoblot analysis, SCOT protein was much reduced. The patient attained normal development and had no permanent ketosis. The accurate diagnosis of SCOT deficiency in this case had a vital impact on the management strategy and outcome.

Resumo em Inglês:

Abstract Fabry disease is a rare cause of end-stage renal disease. Renal pathology is notable for diffuse deposition of glycosphingolipid in the renal glomeruli, tubules, and vasculature. Classical patients with mutations in the α-galactosidase A gene accumulate globotriaosylceramide and become symptomatic in childhood with pain, gastrointestinal disturbances, angiokeratoma, and hypohidrosis. Classical patients experience progressive loss of renal function and hypertrophic cardiomyopathy, with severe clinical events including end-stage renal disease, stroke, arrhythmias, and premature death. The pathophysiological mechanisms by which endothelial cells, podocytes, smooth muscle cells, and tubular dysfunction occur in Fabry disease are poorly characterized and understood. This review evaluates the new evidence in pathophysiology of Fabry nephropathy, highlighting the necessity of early identification of individuals with Fabry disease.

Resumo em Inglês:

Abstract Although Fabry disease was identified a century ago, it is still a challenging condition to diagnose and treat. Registries data suggest that at least 10% of patients may first present with a cardiac event and that cardiac disease is 1 of the 3 major causes of morbidity and mortality in affected males and females. Cardiac involvement in Fabry disease may be expressed as left ventricular hypertrophy (LVH), coronary disease, atrioventricular conduction disturbances, arrhythmias, and valvular involvement. The exact mechanism by which hypertrophy and fibrosis in the heart occur is not fully understood. Lysosomal globotriaosylceramide accumulation in the myocardium is responsible for only 3% of the mass in the hypertrophic heart, indicating that the LVH is not a direct result of substrate infiltration. One of the most important contributions that cardiologists can make is to consider the diagnosis of Fabry disease in patients with cardiac manifestations preceding the development of LVH and conduct family screening to identify patients with early cardiac involvement which will benefit more from enzyme replacement therapy (ERT). Fabry patients without cardiac manifestations of the disease should be evaluated annually by a cardiologist specialized in Fabry disease, regardless of the indication for ERT.

Resumo em Inglês:

Abstract Isolated angiokeratomas (AKs) are common cutaneous lesions, generally deemed unworthy of further investigation. In contrast, diffuse AKs should alert the physician to a possible diagnosis of Fabry disease (FD). Angiokeratomas often do not appear until adolescence or young adulthood. The number of lesions and the extension over the body increase progressively with time, so that generalization and mucosal involvement are frequent. Although rare, FD remains an important diagnosis to consider in patients with AKs, with or without familial history. Dermatologists must have a high index of suspicion, especially when skin features are associated with other earlier symptoms such as acroparesthesia, hypohidrosis, or heat intolerance. Once the diagnosis is established, prompt screening of family members should be performed. In all cases, a multidisciplinary team is necessary for the long-term follow-up and treatment.

Resumo em Inglês:

Abstract Fabry disease is a rare, X-linked lysosomal storage disorder resulting from deficient α-galactosidase A activity and globotriaosylceramide accumulation throughout the body. This accumulation leads to various clinical disorders, including inner ear lesions, with sensorineural hearing loss and dizziness. Although hearing loss is recognized in these patients, its incidence and natural history have not been characterized. Hearing disorders develop mainly in adulthood, and tinnitus may be an earlier symptom in Fabry disease. A significant incidence of mid- and high-frequency sensorineural hearing loss in affected males is commonly reported, whereas in female carriers, it is much less frequent. In addition, a high incidence of vestibular disorders with dizziness and chronic instability is also observed in these patients. The few studies about the effects of enzyme replacement therapy (ERT) on cochleovestibular symptoms show controversial results. Based on the model of densely stained material accumulation in the inner ear, stria vascularis cell, and organ damage, an early indication of ERT may prevent hearing loss due to the reduction in substrate accumulation.

Resumo em Inglês:

Abstract Advances in mass spectrometry have allowed for expansion of newborn screening test panels over the last decade but with increased numbers of disorders have come increased concerns with false-positive rates. The introduction of second-tier testing has improved the specificity of screening for a number of disorders without any corresponding sacrifice in sensitivity. Such testing does, however, put pressure on scarce laboratory resources including instrument and personnel time and even the bloodspot sample itself. The British Columbia Newborn Screening Program has developed an integrated second-tier screening approach to improve test performance without the requirement to resample and reprocess the original bloodspot specimen. By utilizing the residual extract from the first-tier assay and introducing a chromatography step as the second tier, we have been able to reduce false-positive rates due to interfering isobaric compounds for 3 different disorders (maple syrup urine disease, isovaleric aciduria, and guanidinoacetate methyltransferase) in a single multianalyte assay.

Resumo em Inglês:

Abstract The isodecyl neopentanoate is an ingredient used in the cosmetic industry to prepare a nipple fissure balm. We report on 12 newborns that showed elevated C5-acylcarnitine levels upon newborn screening following treatment with balm. The first 3 neonates were immediately recalled for confirmatory tests and resulted negative for both isovaleric acidemia and short/branched chain acyl-CoA dehydrogenase deficiency. In the other 9 cases, the immediate recall was avoided by applying a new second-tier test able to confirm the presence of pivaloylcarnitine. The concentration of C5-acylcarnitine was measured in the days following the suspension of balm application. Abnormal concentrations of C5-acylcarnitine did not seem to be associated with free carnitine deficiency, probably due to the short time of exposure. A direct correlation between balm ingestion and the elevation in pivaloylcarnitine has been demonstrated in 10 adult volunteers. The commercial balm containing a pivalic acid derivative is causal of false-positive results during newborn screening, and it could have the potential to cause secondary carnitine deficiency when used chronically.

Resumo em Inglês:

Abstract The collection of dried blood spots (DBSs) on filter paper has been a powerful tool in newborn screening (NBS) programs and in other fields. However, filter paper has been associated with some level of imprecision due to the filter paper matrix effect. In order to minimize measurement variations, these interferences should be evaluated by NBS assays. The aim of this study is to evaluate the performance of genetic screening processor (GSP) equipment in comparison with a widely used AutoDELFIA and to discuss the limitations and advantages of this new technology in NBS. We evaluated the performance of 3 NBS assays in DBS using GSP in comparison with AutoDELFIA. To determine the inaccuracy and the intra-assay precision, a comparative study and a replication experiment were performed. In the comparative study, human thyroid-stimulating hormone (hTSH) assay showed the highest correlation coefficient, followed by 17α-OH-progesterone and immunoreactive trypsinogen (IRT) assays. The results of the present study suggest that the GSP equipment and kits are suitable for implementation and have acceptable performance for NBS routine. Genetic screening processor assay tends to underestimate hTSH and IRT concentrations in the clinically relevant range when compared to AutoDELFIA assays. More studies are necessary to reevaluate cutoff values. Furthermore, the equipment has advantages when compared with AutoDELFIA, such as methodology with more specificity, reduction in the processing time, and randomized routine. This helps promoting faster dynamic technical processes and faster report generation.

Resumo em Inglês:

Abstract The ultramicroanalytic system (SUMA), created in the 1980s, is a complete system of reagents and instrumentation to perform ultramicroassays combining the sensitivity of the micro-enzyme-linked immunosorbent assay (ELISA) tests with the use of ultramicrovolumes. This technology permitted establishing large-scale newborn screening programs (NSPs) for metabolic and endocrine disorders in Cuba. This article summarizes the main results of the implementation during the 30 years of SUMA technology in NSP for 5 inherited metabolic diseases, using ultramicroassays developed at the Department of Newborn Screening at the Immunoassay Center. Since 1986, SUMA technology has been used in the Cuban NSP for congenital hypothyroidism, initially studying thyroid hormone in cord serum samples. In 2000, a decentralized program for the detection of hyperphenylalaninemias using heel dried blood samples was initiated. These successful experiences permitted including protocols for screening congenital adrenal hyperplasia, galactosemia, and biotinidase deficiency in 2005. A program for the newborn screening of CH using the thyroid-stimulating hormone Neonatal ultramicro-ELISA was fully implemented in 2010. Nowadays, the NSP is supported by a network of 175 SUMA laboratories. After 30 years, more than 3.8 million Cuban newborns have been screened, and 1002 affected children have been detected. Moreover, SUMA technology has been presented in Latin America for over 2 decades and has contributed to screen around 17 million newborns. These results prove that developing countries can develop appropriate diagnostic technologies for making health care accessible to all.

Resumo em Inglês:

Abstract Gyrate atrophy of the choroid and retina (GACR) is a hereditary form of progressive blindness caused by homozygosity for loss-of-function mutations in the ornithine aminotransferase gene (Oat). The high levels of circulating ornithine that lead to ophthalmic symptoms in young adults are also displayed by 2 ornithine aminotransferase (OAT)-deficient mouse models of GACR. Here, we have developed an inexpensive and quantitative bacteria-based test for detecting hyperornithinemia in blood or urine samples from these mutant mice, a test that we suggest could be used to facilitate the identification and treatment of OAT-deficient humans before the onset of visual impairment.

Resumo em Inglês:

Abstract Phenylalanine analysis for phenylketonuria (PKU) detection in newborn screening (NBS) was chosen as the model system to describe how advancements in laboratory technology improved laboratory performance. These advancements have made NBS programs better and have improved the health outcomes of the affected newborn through improvements in accurate early detection over the past 50 years. The most current state-of-the-art technology, tandem mass spectrometry (MS/MS), has proven that it is now the choice in almost all modern NBS facilities because it is a versatile instrument that continues to grow in its application not just for amino acid and acylcarnitine detection but for other metabolites and disorders such as lysosomal storage diseases and second-tier detection of some screen-positive results. The use of MS/MS will continue to expand, even with the anticipated introduction and expansion of molecular screening methods into NBS programs. Regarding technological advancements, the future of NBS will include even newer technologies and approaches that will enhance the detection and treatment of newborns affected by PKU and other inborn errors of metabolism.

Resumo em Inglês:

Abstract The glycogen storage diseases (GSDs) comprise a group of rare inherited disorders of glycogen metabolism. The hepatic glycogenolytic forms of these disorders are typically associated with hypoglycemia and hepatomegaly. For GSD I, secondary metabolic disturbances include fasting hyperlactatemia, hyperuricemia, and hyperlipidemia. Glycogen storage disease III is caused by reduced activity of the debrancher enzyme, GSD VI by phosphorylase, and GSD IX by phosphorylase kinase. It has often been reported that the non-GSD I group of disorders have a benign course. However, myopathy, cardiomyopathy, and cirrhosis have been reported significant clinical morbidities associated with GSD III and IX in particular. There have been a range of reports indicating high-protein diets, high-fat diets, medium chain triglyceride (MCT), modified Atkins diet, and therapeutic ketones as rescuing severe phenotypes of GSD III in particular. The etiology of these severe phenotypes has not been defined. Cases presented in this report indicate potential harm from excessive simple sugar use in GSD IX C. Review of the literature indicates that most interventions have reduced the glycemic load and provide alternate substrates for energy in rescue situations. Prevention of complications is most likely to occur with a mixed balanced low glycemic index diet potentially with relative increases in protein.

Resumo em Inglês:

Abstract Lysosomes were originally described in the early 1950s by de Duve who was also the first to recognize the importance of these organelles in human disease. We know now that lysosomes are involved in numerous biological processes, and abnormalities in lysosomal function may result in a broad range of diseases. This review will briefly discuss the role of lysosomes in inflammation and how disruption of normal lysosomal function in the lysosomal storage diseases (LSDs) leads to abnormalities in inflammation and immunity.

Resumo em Inglês:

Abstract Adults with phenylketonuria (PKU) experience disturbances in mood. This study used qualitative and quantitative techniques to adapt the 65-item Profile of Mood States (POMS) for the assessment of key mood domains in adults with PKU. First, cognitive interviews on 58 POMS items (excluding 7 Friendliness domain items) among 15 adults and adolescents (age ≥16 years) with PKU were conducted to eliminate items poorly understood or considered irrelevant to PKU; 17 items were removed. Next, the remaining POMS items were quantitatively examined (Mokken scaling and Rasch analysis) in 115 adult patients with PKU. An additional 21 items were removed iteratively, resulting in the 20-item draft PKU-POMS. Finally, the psychometric properties of the draft PKU-POMS were examined. The instrument displayed strong psychometric properties (reliability, validity, and responsiveness) over 6 domains (Anxiety, Depression, Anger, Activity, Tiredness, and Confusion) and all items were well understood in the final cognitive interviews with 10 adults with PKU.

Resumo em Inglês:

Abstract Content validity of the 18-item Investigator-Rated Attention-Deficit Hyperactivity Disorder (ADHD) Rating Scale IV (I-ADHD RS-IV) with adult prompts was investigated using qualitative interviews of US clinicians who had prior experience rating adults with phenylketonuria (PKU) using the I-ADHD RS-IV. Fourteen qualitative interviews were conducted to obtain key symptom experiences of adults with PKU and assessed the relevance, clarity, and administration of the I-ADHD RS-IV. Participants (n = 13, 92.9%) endorsed the inattention symptoms as key experiences by adults with PKU and endorsed the instrument as fit for purpose for adults with PKU. Participants generally reported low frequencies of occurrence for the 9 I-ADHD RS-IV hyperactivity/impulsivity items. Despite some clinicians’ concerns for the lack of patient self-awareness, the participants reported no difficulty selecting a rating on these items. This in-depth study of the content validity of the I-ADHD RS-IV provides evidence that this clinician-reported instrument captures the severity of important inattention symptoms in adults with PKU.

Resumo em Inglês:

Abstract Newborn screening (NBS) for phenylketonuria in Latin America gave its first step in an organized way 3 decades ago when the first national NBS program was implemented in Cuba. From then onward, it experienced a slow but continuous growing, being currently possible to find from countries where no NBS activity is known to several countries with consolidated NBS programs. This complex scenario gave rise to a great diversity in the criteria used for sample collection, selection of analytical methods, and definition of cutoff values. Considering this context, a consensus meeting was held in order to unify such criteria, focusing the discussion in the following aspects—recommended blood specimens and sample collection time; influence of early discharge, fasting, parenteral nutrition, blood transfusions, extracorporeal life support, and antibiotics; main causes of transient hyperphenylalaninemias; required characteristics for methods used in phenylalanine measurement; and finally, criteria to define the more appropriate cutoff values.

Resumo em Inglês:

Abstract Phenylketonuria (PKU) is caused by a deficient activity of enzyme phenylalanine (Phe) hydroxylase, which results in high Phe blood concentration, which is toxic to the central nervous system. The fundamental purpose of nutritional treatment is to reduce and maintain blood Phe between 2 mg/dL (120 µmol/L) and 6 mg/dL (360 µmol/L) in order to prevent neuropathogenic complications. At the same time, nutrition support must provide enough energy and nutrients to promote normal growth and development and also to avoid vitamin and mineral deficiencies. Phenylketonuria treatment must be maintained long-life and its adherence must be frequently assessed. The amount of Phe required by patients with PKU varies throughout life and must be adjusted according to individual tolerance, residual phenylalanine hydroxylase enzymatic activity, age, sex, growth rate, protein intake, and nutritional and biochemical status among others. Treatment must be done by trained personnel. It is necessary to unify treatment criteria and further research must be done.

Resumo em Inglês:

Abstract Patients with glycogen storage disease (GSD) are either orally fed (ORF) or gastronomy-tube fed (GTF) with cornstarch to maintain normal glucose levels. It is not known whether the use of cornstarch affects the microbiological oral profile of patients with GSD. Thus, the purpose of this study was to compare supragingival and subgingival plaque samples collected from 53 participants with GSD (2-56 years)—29 ORF and 24 GTF. The 16S sequence bacterial profiles of plaque DNA were obtained and a total of 768 probes were detected across the plaque groups. Orally fed patients showed higher means of cariogenic species and periodontal health-associated species, whereas GTF patients showed higher means of periopathogenic species (P < .05). Orally fed patients exhibited high levels of caries pathogens and lower levels of periodontal pathogens possibly due to the acidic environment created by their cornstarch diet, when compared to GTF patients.

Resumo em Inglês:

Abstract Glycogen storage disease type IXa (GSD IXa) presents in childhood with hepatomegaly, poor growth, and ketotic hypoglycemia. Clinical course is usually mild, often not requiring treatment with attenuation of symptoms with increasing age. The phenotypic spectrum has recently expanded to include more severe involvement with hepatic fibrosis or cirrhosis warranting dietary therapy. We report a 2-year-old boy with a severe phenotype of GSD IXa presenting with a massive hepatomegaly, significant transaminitis, recurrent ketotic hypoglycemia, and short stature. Aggressive dietary management with regular feeds, frequent uncooked cornstarch doses, and protein supplementation resulted in clinical improvements including enhanced growth velocity, energy levels, overall well-being, and reduction in hepatomegaly with restitutions in biochemical parameters. We concur with a recent report which proposed that GSD IXa is not always a mild condition but instead part of an expanding phenotypic spectrum warranting intensive dietary management to optimize metabolic control and quality of life.

Resumo em Inglês:

Abstract In the last decades, it has become more and more evident that lysosomal storage disorders and common neurodegenerative diseases such as Alzheimer and Parkinson diseases have clinical, neuropathological, and genetic features in common, including lysosomal dysfunction and impaired autophagy. Patients with Gaucher and even carriers of Gaucher disease have an increased risk to develop Parkinson disease. Likewise, individuals who are heterozygous for a mutation of a gene that causes an adult form of neuronal ceroid lipofuscinosis are more likely to be affected by a form of frontotemporal dementia in their later life. A further example is the gene NAGLU encoding the enzyme α-N-acetylglucosaminidase, which is deficient in patients with mucopolysaccharidosis type IIIB. Mutations of the NAGLU gene have been observed in patients affected by an axonal neuropathy. An interesting unexpected finding was the link between stuttering and genes that are essential for the function of all lysosomal enzymes. This review will present some example of the association of lysosomal storage disorders and neurodegenerative disease and discuss possible pathogenic mechanisms that are common to both conditions. The understanding of the pathophysiology of the endosomal–lysosomal–autophagic system may help to develop drugs, which might provide benefit not only for patients with rare lysosomal storage disorders but also for individuals affected by more common diseases.

Resumo em Inglês:

Abstract Fabry disease is an inherited metabolic disorder characterized by progressive lysosomal accumulation of glycolipids in a variety of cell types, including neural cells. Small, unmyelinated nerve fibers are particularly affected and small fiber peripheral neuropathy often clinically manifests at a young age. Neuropathic pain and pain attacks are often the presenting symptoms of the disease and start at an average age of 9 years in male patients and 16 years in female patients, but currently a systematic literature review in early childhood showed the presence of these symptoms before the age of 5 years. Clinical studies have shown that enzyme replacement therapy may improve the overall pain scores and pain intensity in patients; improvements in pain outcomes have been sustained during the long-term follow-up, allowing many patients to reduce their use of pain medication. Some indirect evidence from dose-switching studies suggests that enzyme replacement therapy dose may be of relevance to pain outcomes. Considering that damage to small nerve fibers occurs early, prompt treatment is important in order to limit damage to the peripheral nervous system. In this article a comprehensive overview of the existing literature on small nerve fiber pathophysiology and the relationship with neuropathic pain and treatment response in children and adults with Fabry disease is presented.

Resumo em Inglês:

Abstract Fabry disease is a rare X-linked disease caused by the deficiency of α-galactosidase that leads to the accumulation of abnormal glycolipid. Untreated patients develop potentially lethal complications by age 30 to 50 years. Enzyme replacement therapy is the current standard of therapy for Fabry disease. Two formulations of recombinant human α-galactosidase A (agalsidase) are available in most markets: agalsidase-α and agalsidase-β, allowing a choice of therapy. However, the US Food and Drug Administration rejected the application for commercialization of agalsidase-α. The main difference between the 2 enzymes is the dose. The label dose for agalsidase-α is 0.2 mg/kg/2 weeks, while the dose for agalsidase-β is 1.0 mg/kg/2 weeks. Recent evidence suggests a dose-dependent effect of enzyme replacement therapy and agalsidase-β is 1.0 mg/kg/2 weeks, which has been shown to reduce the occurrence of hard end points (severe renal and cardiac events, stroke, and death). In addition, patients with Fabry disease who have developed tissue injury should receive coadjuvant tissue protective therapy, together with enzyme replacement therapy, to limit nonspecific progression of the tissue injury. It is likely that in the near future, additional oral drugs become available to treat Fabry disease, such as chaperones or substrate reduction therapy.

Resumo em Inglês:

Abstract Folate plays a central role in DNA synthesis and methylation, which are essential for DNA integrity maintenance and gene expression. Folate deficiency may lead to the incorporation of uracil into DNA and chromosome breaks, increasing the risk of cancer. However, conflicting evidence has been observed depending on the type of epidemiological study, dietary or circulating folate, and the type of cancer. New concern has arisen after a mandatory folic acid (FA) fortification program adopted for the prevention of neural tube defects in the United States, which suggested an increase in the incidence of colorectal cancer. In the present article, folate status and cancer are under review, and a discussion of the challenge of assessing folate status through food intake, supplement use, FA fortification programs, circulating folate, and the interaction of diet and the polymorphism of the enzyme involved in folate metabolism will be presented.

Resumo em Inglês:

Abstract Guanidinoacetate methyltransferase (GAMT) deficiency is an autosomal recessively inherited disorder of the metabolism of creatine that leads to depleted levels of creatine and excessive concentrations of guanidinoacetate (GAA). Patients affected develop neurological symptoms during childhood, such as muscular hypotonia, involuntary extrapyramidal movements, convulsions, slurred speech, and even autism. Although the pathophysiology of GAMT deficiency is unclear, neurological dysfunction is commonly found in this disease, and it has been mainly attributed to a reduction in creatine or/and an increase in GAA levels. Reports from literature suggest that GAA may interfere with neuronal γ-aminobutyric acid (GABA) receptors type A and cause epilepsy in human. Preclinical studies show that GAA increases free radical formation and decreases brain antioxidant defenses, inducing alteration in oxidative status. Guanidinoacetate also impairs energy metabolism in brain. The discussion of this review focuses on various and latest studies addressing GAMT deficiency and creatine metabolism, as well as addresses the question of neurotoxicity GAA.

Resumo em Inglês:

Abstract Glycogen storage disease type 1 (GSD1) is an inherited disorder caused by impaired glucose 6-phosphatase activity. This impairment translates into the inhibition of endogenous glucose production and the subsequent accumulation of cellular glucose 6-phosphate. Excess glucose 6-phosphate enhances glycolysis, increases the production of fatty acids, uric acid, and lactate, causes hepatomegaly due to glycogen and lipid accumulation, and finally results in liver tumor development. Although the exact mechanisms of tumorigenesis in patients with GSD1 remain unclear, GSD1 hepatocytes undergo a Warburg-like metabolic switch. The consequent hyperactivation of specific metabolic pathways renders GSD1 hepatocytes susceptible to tumor development, presumably by providing the building blocks and energy required for cell proliferation. In addition to this, enhanced apoptosis in GSD1 may promote mitotic activity and hence result in DNA replication errors, thereby contributing to tumorigenesis. Increased carbohydrate responsive element-binding protein (ChREBP) and mammalian target of rapamycin (mTOR) activity and impaired AMP-activated protein kinase (AMPK) function likely play key roles in these pro-oncogenic processes.

Resumo em Inglês:

Abstract The mucopolysaccharidosis (MPS) disorders are rare genetic diseases caused by deficiencies in lysosomal enzymes involved in the degradation of glycosaminoglycans, leading to pulmonary, cardiac and neurological dysfunctions, skeletal anomalies, impaired vision, and/or hearing and shortened life spans. Whereas in the past, few individuals with MPS reached adulthood, better diagnosis, multidisciplinary care, and new therapies have led to an increasing number of adult patients with MPS. Therefore, fertility and pregnancy questions in this patient population are becoming more important. Management of fertility issues and pregnancy in patients with MPS is challenging due to the lack of documented cases and a dearth in the literature on this topic. This review presents multidisciplinary expert opinions on managing fertility and pregnancy based on case studies and clinical experience presented at a meeting of MPS specialists held in Berlin, Germany, in April 2015. An overview of the existing literature on this subject is also included.

Resumo em Inglês:

Abstract Fanconi-Bickel syndrome (FBS), also known as glycogen storage disease type XI (GSD XI), is a rare autosomal recessive disorder of carbohydrate metabolism. It is caused by mutations in the gene SLC2A2, which encodes for the facilitative glucose transporter GLUT2. Diagnosis of FBS is often delayed since the clinical features and laboratory markers often overlap with other disorders whose characteristic features include short stature, fasting hypoglycemia, postprandial hyperglycemia, hepatomegaly, hypophosphatemic rickets, and proximal renal tubular dysfunction. In this article, we present a case of FBS and its management in an African American female who initially presented with persistent proximal tubulopathy, hypercalciuria, and metabolic acidosis. We also include a recent literature review on FBS and discuss other metabolic disorders that should be considered in the differential diagnosis.

Resumo em Inglês:

Abstract Fabry disease (FD) is an X-linked, lysosomal storage disorder caused by a mutation in the alpha galactosidase (GLA) gene leading to a deficiency in α-galactosidase A enzyme (α-Gal A) activity, which in turn results in accumulation of glycosphingolipids in different cells. The 2 major clinical phenotypes are the classic severe phenotype and the milder, later onset phenotype. In severe affected males with little or no α-Gal A activity, the onset of acroparesthesias, hypohidrosis, angiokeratomas, and corneal dystrophy is typically observed in childhood or adolescence. With advancing age, progressive multisystem microvasculopathic disease culminates in renal failure, cardiomyopathy, and/or cerebrovascular disease. Patients with later onset have residual enzyme activity and lack of vascular endothelial glycolipid accumulations; thus, they do not present with the early manifestations of the classic phenotype and typically present cardiac or renal disease in the fourth to seventh decade. Although the pathogenesis of cerebral vasculopathy in FD is poorly understood, it can be hypothesized that white matter changes may reflect the pathophysiology of the disease.

Resumo em Inglês:

Abstract The Fabry Outcome Survey (FOS) is an international long-term observational registry sponsored by Shire for patients diagnosed with Fabry disease who are receiving or are candidates for therapy with agalsidase alfa (agalα). Established in 2001, FOS provides long-term data on agalα safety/efficacy and collects data on the natural history of Fabry disease, with the aim of improving clinical management. The FOS publications have helped establish prognostic and severity scores, defined the incidence of specific disease variants and implications for clinical management, described clinical manifestations in special populations, confirmed the high prevalence of cardiac morbidity, and demonstrated correlations between ocular changes and Fabry disease severity. These FOS data represent a rich resource with utility not only for description of natural history/therapeutic effects but also for exploratory hypothesis testing and generation of tools for diagnosis/management, with the potential to improve future patient outcomes.

Resumo em Inglês:

Abstract Next-generation sequencing (NGS) panels are used widely in clinical diagnostics to identify genetic causes of various monogenic disease groups including neurometabolic disorders and, more recently, lysosomal storage disorders (LSDs). Many new challenges have been introduced through these new technologies, both at the laboratory level and at the bioinformatics level, with consequences including new requirements for interpretation of results, and for genetic counseling. We review some recent examples of the application of NGS technologies, with purely diagnostic and with both diagnostic and research aims, for establishing a rapid genetic diagnosis in LSDs. Given that NGS can be applied in a way that takes into account the many issues raised by international consensus guidelines, it can have a significant role even early in the course of the diagnostic process, in combination with biochemical and clinical data. Besides decreasing the delay in diagnosis for many patients, a precise molecular diagnosis is extremely important as new therapies are becoming available within the LSD spectrum for patients who share specific types of mutations. A genetic diagnosis is also the prerequisite for genetic counseling, family planning, and the individual choice of reproductive options in affected families.

Resumo em Inglês:

Abstract Since Christian de Duve first described the lysosome in the 1950s, it has been generally presented as a membrane-bound compartment containing acid hydrolases that enables the cell to degrade molecules without being digested by autolysis. For those working on the field of lysosomal storage disorders, the lack of one such hydrolase would lead to undegraded or partially degraded substrate storage inside engorged organelles disturbing cellular function by yet poorly explored mechanisms. However, in recent years, a much more complex scenario of lysosomal function has emerged, beyond and above the cellular “digestive” system. Knowledge on how the impairment of this organelle affects cell functioning may shed light on signs and symptoms of lysosomal disorders and open new roads for therapy.

Resumo em Inglês:

Abstract Beta-ketothiolase deficiency is an inherited disorder of ketone body metabolism and isoleucine catabolism. It typically manifests as recurrent ketoacidotic episodes with characteristic abnormalities in the urinary organic acid profile. However, several challenges in the diagnosis of beta-ketothiolase deficiency have been encountered: atypical presentations have been reported and some other disorders, such as succinyl-CoA:3-oxoacid CoA transferase and 2-methyl-3-hydroxybutyryl-CoA dehydrogenase deficiencies, can mimic the clinical and/or biochemical signs of beta-ketothiolase deficiency. A final diagnosis of beta-ketothiolase deficiency requires an enzymatic assay and/or a molecular analysis, but some caveats must be considered. Despite the reported missed cases, screening programs have successfully identified an increasing number of patients with beta-ketothiolase deficiency. Early diagnosis and management of beta-ketothiolase deficiency will enable prevention of its serious acute and chronic complications and ultimately improve the prognosis.

Resumo em Inglês:

Abstract Anderson-Fabry disease (AFD) is a rare inherited X-linked disease, caused by mutations of the gene encoding the α-galactosidase A enzyme, that leads to a deficiency or absence of its activity with consequent accumulation of globotriaosylceramide (Gb3) and other glycosphingolipids in the lysosomes of several cells types in the organism, mainly the endothelial, nervous system, cardiac, and renal cells. Its heterogeneous and nonspecific presentation, similar to other common pathologies, delays the diagnosis and leads to incorrect therapy. In the presence of attenuated phenotypes with predominant involvement of an organ, it is even harder to identify patients with AFD. It is highly important to be aware of this diagnosis, since enzyme replacement therapy is currently available. This review aims to approach the clinical manifestations of AFD and the phenotypes related to the differential diagnosis for each manifestation and the frequency of follow-up recommended.

Resumo em Inglês:

Abstract Lysosomal storage disorders are rare genetic disorders due to deficient lysosomal activity, which leads to progressive accumulation of nonmetabolized substrates. Patient’s clinical outcomes have significantly improved since the advent of enzyme replacement therapy, even though this therapeutic approach presents important limitations, such as immune reactions, low bioavailability of recombinant enzymes, and incapability to reach the central nervous system. New strategies based on gene therapy or small molecules have been proposed and tested as an alternative to enzyme replacement therapy or to complement it. Small molecules are orally administrated, no antigenic compound that can diffuse across cell membranes and distribute in steady-state concentrations, also reaching the central nervous system. Substrate reduction therapy, pharmacological chaperones, and stop-codon read-through enhancers are small molecules currently available for the treatment of lysosomal storage disorders. This article describes the characteristics of this class of compounds and the possible strategies to improve their efficiency in future development.

Resumo em Inglês:

Abstract Fabry disease is a multisystemic disorder with consequent morbidity and mortality at an early age in patients of both genders. Although renal failure has been previously described as the cause of death with the highest prevalence, recent studies, based on the analysis of the population recorded in the Fabry Registry, reported that 40% of deaths had a cardiovascular origin. Data from the same registry emphasize the high risk for these patients suffering cardiovascular events—particularly acute myocardial infarction—and to the fact that this risk is higher for those patients who need dialysis. Microvascular dysfunction is a constant in patients with Fabry disease, which affects young patients, independently from other cardiac involvement manifestations—such as left ventricular hypertrophy—and from the patient’s gender.

Resumo em Inglês:

Abstract All newborn screening laboratories in the United States and many worldwide screen for cystic fibrosis. Most laboratories use a second-tier genotyping assay to identify a panel of mutations in the CF transmembrane regulator (CFTR) gene. Centers for Disease Control and Prevention’s Newborn Screening Quality Assurance Program houses a dried blood spot repository of samples containing CFTR mutations to assist newborn screening laboratories and ensure high-quality mutation detection in a high-throughput environment. Recently, CFTR mutation detection has increased in complexity with expanded genotyping panels and gene sequencing. To accommodate the growing quality assurance needs, the repository samples were characterized with several multiplex genotyping methods, Sanger sequencing, and 3 next-generation sequencing assays using a high-throughput, low-concentration DNA extraction method. The samples performed well in all of the assays, providing newborn screening laboratories with a resource for complex CFTR mutation detection and next-generation sequencing as they transition to new methods.