ABSTRACT
Abstract Background: Mucopolysaccharidosis type II, also known as Hunter syndrome, is a rare X-linked recessive disorder caused by deficiency of the lysosomal enzyme Iduronate-2- Sulfatase (IDS), leading to progressive accumulation of Glycosaminoglycans (GAGs) in several organs. Over the years, Enzyme Replacement Therapy (ERT) has provided significant benefits for patients, retarding the natural progression of the disease. Results: The authors evaluated 17 patients from the same family with a mild form of MPS type II; the proband had developed acute decompensated heart failure refractory to clinical measurements at 23 years and needed a rather urgent heart transplant; however, he died from surgical complications shortly after the procedure. Nevertheless, subsequent to his tragic death, 16 affected male relatives were detected after biochemical tests identifying the low or absent activity of the IDS enzyme and confirmed by molecular analysis of the IDS gene. Following diagnosis, different options of treatment were chosen: 6 patients started ERT with Elaprase® (Idursulfase) soon after, while the other 10 remained without ERT. Eventually, 4 patients in the latter group began ERT with Hunterase® (Idursulfase Beta). None presented adverse effects to either form of the enzyme. Among the 6 individuals without any ERT, two died of natural causes, after reaching 70 years. Despite the variable phenotype within the same family (mainly heart dysfunctions and carpal tunnel syndrome), all 14 remaining patients were alive with an independent lifestyle. Conclusion: Here, the authors report the variable progress of the disease with and without ERT in a large Brazilian family with a slowly progressive form of MPS II, harboring the same missense variant in the IDS gene.
ABSTRACT
ABSTRACT Purpose: to describe the audiological characteristics of patients with mucopolysaccharidosis. Methods: after formulating the research question, three databases were considered for the search (Science Direct, Virtual Health Library and Web of Science); the following descriptors were used: mucopolysaccharidoses, hearing loss, and audiology. Articles were included that were original and complete, presenting audiological evaluation data in patients with mucopolysaccharidosis. Each study was classified according to the degree of recommendation and the level of scientific evidence, based on the criteria established by the Oxford Center for Evidence-based Medicine, and the results obtained from the evaluations were analyzed. Results: of the 499 articles found, eight met the inclusion criteria. Pure tone audiometry and tympanometry were performed in all studies. The incidence of hearing loss in patients with MPS ranged from 54% to 100% of the cases, with conductive hearing loss corresponding to 30% and 58.33%, mixed hearing loss corresponding to 28.5% and 66.66% and sensorineural hearing loss corresponding to less than 14%. None of the studies described the responses of otoacoustic emissions and auditory evoked potentials. Conclusion: the prevalence of hearing loss among individuals with MPS is higher than 54% of the cases, of which conductive and mixed are predominant.
RESUMO Objetivo: descrever as características audiológicas de pacientes com Mucopolissacaridose. Métodos: após formular a pergunta de pesquisa, foram consideradas três bases de dados (Science Direct, Biblioteca Virtual em Saúde e Web of Science), sendo utilizados os seguintes descritores: mucopolissacaridoses, perda auditiva, audiologia. Foram incluídos artigos originais e completos, que apresentavam dados de avaliação audiológica em pacientes com mucopolissacaridose. Cada estudo foi classificado de acordo com o grau de recomendação e o nível de evidência científica, baseado nos critérios estabelecidos pela Oxford Centre for Evidence-based Medicine, e foram analisados os resultados obtidos nas avaliações. Resultados: dentre os 499 artigos encontrados, oito contemplaram os critérios de inclusão. A audiometria tonal e a timpanometria foram realizadas em todos os estudos. A incidência de perda auditiva em pacientes com MPS variou entre 54% a 100% dos casos, sendo que as perdas auditivas condutivas corresponderam à 30% e 58,33%, as perdas auditivas mistas corresponderam à 28,5% e 66,66% e as perdas auditivas neurossensoriais corresponderam à menos de 14%. Nenhum dos estudos descreveu as respostas das emissões otoacústicas e dos potenciais evocados auditivos. Conclusão: a prevalência de perda auditiva entre indivíduos com MPS é superior à 54% dos casos, sendo esta predominantemente condutiva e mista.