BACKGROUND: phenylketonuria is a genetic disorder that causes biochemical alterations, leading to a deficiency in the synthesis of proteins and neurotransmitters and thereby hindering the myelination process. Structural and functional changes in myelin can alter neural conductivity patterns and or reduce synaptic connection in individuals with phenylketonuria. Essentially, a dietary treatment should be implemented in the first weeks of life in order to avoid clinical and biochemical manifestations of the disease. When diet is continually maintained, children with phenylketonuria show normal development. However, deficits in executive functions, interhemispherical interaction, language and memory have been observed even in children with early treatment and appropriate diet. Some researches were carried out for investigating the relationship between phenylketonuria and alterations in the hearing function. PURPOSE: to systematically review articles dedicated to the research of relationship between hearing disorders and hyperphenylalaninaemias, highlighting the classic phenylketonuria. The bibliographical references were obtained through research in the databases: Lilacs, Medline, Cochrane Library and Scielo and through search in the reference list of the identified and selected articles. CONCLUSION: the relationship among hyperphenylalaninaemias, including phenylketonuria, and hearing alterations is still controversial in the literature. It is suggested that more investigations as for the hearing function are necessary on those individuals in order to elucidate this possible relationship.
Phenylketonurias; Hearing Disorders; Evoked Potentials, Auditory; Evoked Potentials, Auditory, Brain Stem