Oropharyngeal Dysphagia in Mucopolysaccharidoses: Evidence from Videofluoroscopic Swallowing Study

Abstract Mucopolysaccharidoses (MPS) are rare inborn errors of metabolism, leading to the accumulation of glycosaminoglycans (GAG) in distinct tissues. We investigated oropharyngeal dysphagia using the videofluoroscopic swallowing study (VFSS) in patients with different MPS types. Since there is a lack of studies systematically evaluating this disorder in this population, the use of a standard technique should contribute to better evaluate individuals with MPS. A cross-sectional and observational study enrolling patients followed by an outpatient service for lysosomal diseases at the Genetics Service of the Hospital de Clínicas de Porto Alegre (SGM/HCPA) was conducted. Patients underwent semi-structured interviews, clinical evaluation and VFSS. Nineteen patients were evaluated, including patients with MPS types I (16%), II (42%), IIIb (10%) and IVa (32%). Nearly all patients (95%) presented with oropharyngeal dysphagia in the VFSS. The most frequent findings were impaired chewing during oral phase (94%) and reduced laryngeal elevation in the pharyngeal phase (72%). Oropharyngeal dysphagia constituted a prevalent symptom in the studied cohort regardless of MPS type. Our data reinforces the notion that this disorder should be objectively assessed since it can significantly compromise the nutrition and the hydration of these patients as well as lead to tracheobronchial aspiration, thus resulting in aspiration pneumonia and even death eventually.

Clinical and Radiological Characterisation of Patients with Mucopolysaccharidosis in a Genetic Clinic

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.

Enfermedad de Fabry en Argentina / Fabry disease in Argentina / Doença de Fabry na Argentina

La enfermedad de Fabry es una patología genética debida a la deficiencia de la enzima α-galactosidasa A. En la Facultad de Ciencias Exactas de la Universidad Nacional de La Plata se implementaron estudios de diagnóstico de enfermedades lisosomales y se comenzó por la Enfermedad de Fabry. Se llevó a cabo un estudio dirigido a la detección de pacientes Fabry no diagnosticados mediante un enfoque biomédico multidisciplinario. Se realizó una evaluación nefrológica de los pacientes argentinos detectados y un análisis de sus manifestaciones clínicas durante el tratamiento de reemplazo enzimático. Los pacientes tratados con agalsidasa alfa recibieron sus primeras infusiones en centros médicos y luego la infusión fue domiciliaria. Los datos de los pacientes argentinos fueron registrados en la base de datos FOS, un registro internacional multicéntrico. Los estudios de investigación básica realizados mostraron la existencia de un estado proinflamatorio en células de pacientes Fabry, lo cual podría explicar parte de su fisiopatología. El abordaje de las enfermedades poco frecuentes no es sencillo, sobre todo ante la falta de políticas sanitarias de parte del Estado. Este trabajo permitió lograr múltiples objetivos: la difusión de la Enfermedad de Fabry en Argentina, mayor sospecha clínica en la comunidad médica y mejor accesibilidad al diagnóstico, seguimiento y tratamiento para los pacientes.

A Fabry disease is an X-linked lysosomal disorder that results from a deficiency of the lysosomal enzyme alpha-galactosidase A. The implementation of biochemical and genetic tests for lysosomal diseases was carried out in our institution, the School of Exact Sciences, Universidad Nacional de La Plata. A successful approach for the detection of Fabry patients in Argentina was developed by constitutingan interdisciplinary group of professionals. A nephrological assessment of the Argentine patients detected was made andthe clinical manifestations of Fabry patients were analysed and recorded in a FOS international registry. Patients received their enzyme replacement therapy, and the infusion was offered at home. Research studies carried out by our group showed the existence of a proinflammatory state in cells from Fabry patients, which could be related to the pathophysiology. Approaching rare diseases is not easy, especially when there is a lack of State health care policies. This work led us to achieve objectives such as disseminate knowledge about the disease in our country, enhance clinical suspicion and improve accessibility to diagnosis and treatment for patients.

Doença de Fabry é uma doença genética que resulta da deficiência da enzima α-galactosidase A. Na Faculdade de Ciências Exatas da Universidade Nacional de La Plata foram implementados estudos de diagnóstico de doenças lisossomais e a primeira foi a Doença de Fabry. Realizou-se um estudo orientado à detecção de pacientes Fabry não diagnosticados mediante uma abordagem biomédica multidisciplinar. Foi feita uma avaliação nefrológica dos pacientes argentinos detectados e uma análise de suas manifestações clínicas durante o tratamento de reposição enzimática. Os pacientes tratados com agalsidase alfa receberam suas primeiras infusões em centros médicos, e depois a infusão foi domiciliar. Os dados dos pacientes argentinos se registraram na base de dados FOS, um registro internacional multicêntrico. Estudos de pesquisa básica realizados mostraram a existência de um estado pró-inflamatório em células de pacientes Fabry, o que poderia explicar parte de sua fisiopatologia. A abordagem das doenças pouco frequentes não é simples, principalmente diante da falta de políticas sanitárias de parte do Estado. Este trabalho permitiu alcançar objetivos múltiplos: a difusão da Doença de Fabry na Argentina, maior suspeita clínica na comunidade médica, e melhor acessibilidade ao diagnóstico, seguimento e tratamento para os pacientes.

Lysosome: The Story Beyond the Storage

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.

Genomic analysis of Brazilian patients with Fabry disease

Fabry disease is an X-linked lysosomal disorder due to a-galactosidase A deficiency that causes storage of globotriaosylceramide. The gene coding for this lysosomal enzyme is located on the long arm of the X chromosome, in region Xq21.33-Xq22. Disease progression leads to vascular disease secondary to involvement of kidney, heart and the central nervous system. Detection of female carriers based solely on enzyme assays is often inconclusive. Therefore, mutation analysis is a valuable tool for diagnosis and genetic counseling. Many mutations of the a-galactosidase A gene have been reported with high genetic heterogeneity, being most mutations private found in only one family. The disease is panethnic, and estimates of incidence range from about 1 in 40,000 to 60,000 males. Our objective was to describe the analysis of 6 male and 7 female individuals belonging to 4 different Fabry disease families by automated sequencing of the seven exons of the a-galactosidase gene. Sequencing was performed using PCR fragments for each exon amplified from DNA extracted from peripheral blood. Three known mutations and one previously described in another Brazilian family were detected. Of 7 female relatives studied, 4 were carriers. Although the present study confirms the heterogeneity of mutations in Fabry disease, the finding of the same mutation previously detected in another Fabry family from our region raises the possibility of some founder effect, or genetic drift. Finally, the present study highlights the importance of molecular analysis for carrier detection and genetic counseling.