Algunos desafíos en mucopolisacaridosis tipo I / A few challenges in mucopolysaccharidosis type I

Se describen como desafíos actuales en mucopolisacaridosis I la necesidad de una clasificación adecuada, vinculándola a las indicaciones terapéuticas; el diagnóstico temprano desde la pesquisa neonatal, sus ventajas y dificultades hasta la sospecha clínica de las formas grave y atenuada; el cuidado de la patología espinal y oftalmológica, desde el diagnóstico, el seguimiento y el tratamiento; las reacciones alérgicas por terapia de reemplazo enzimático, su diagnóstico y tratamiento. Por último, la transición hacia el cuidado adulto

Here we describe the current challenges of mucopolysaccharidosis type I: the need for an adequate classification, establishing its relationship to therapeutic indications; an early diagnosis, from neonatal screening, its advantages and barriers, to clinical suspicion of severe and attenuated forms; spinal and eye disease care, from diagnosis to follow-up and treatment; allergic reactions caused by enzyme replacement therapy, their diagnosis and treatment. And lastly, transition to adult care

Nuevas recomendaciones para el cuidado de los pacientes con mucopolisacaridosis tipo I / New recommendations for the care of patients with mucopolysaccharidosis type I

Dados los avances sobre mucopolisacaridosis Icon posterioridad al consenso publicado en la Argentina por un grupo de expertos en 2008, se revisan recomendaciones respecto a estudios genéticos, seguimiento cardiológico, cuidado de la vía aérea, alertas sobre aspectos auditivos, de la patología espinal y neurológica. Se hace revisión de la terapéutica actual y se enfatiza en la necesidad de un diagnóstico y tratamiento precoces, así como de un seguimiento interdisciplinario

Considering the advances made on mucopolysaccharidosis type I after the consensus study published by a group of experts in Argentina in 2008, recommendations about genetic testing, cardiological follow-up, airway care, hearing impairment detection, spinal and neurological conditions, as well as current treatments, were reviewed. Emphasis was placed on the need for early diagnosis and treatment, as well as an interdisciplinary follow-up

A novel compound mutation in alpha-L-iduronidase gene causes mucopolysaccharidosis type

Mucopolysaccharidosis type I (MPSI) is a rare autosomal recessive disorder caused bymutations in alpha-L-iduronidase (IDUA) gene. IDUA contributes to the degradation of the glycosaminoglycans, including heparan sulphate and dermatan sulphate. Deficient activity of IDUA generates accumulation of glycosaminoglycans in lysosomes leading to MPS I. Here, we identified twoboys with MPS I caused by a compound heterozygote of a reported c.265C > T (p.R89W) missense mutation in exon 2 and a novel c.1633G > T (p.E545*, 109) nonsense mutation in exon 11 of IDUA gene in a Chinese family. R89 is close to the active site and its replacement will affect the structure and function of IDUA. Besides, termination from E545 deletes one of the prominent domainsand alters the spatial structure of IDUA. In conclusion, our study demonstrates a previously unrecognized mutation in IDUA gene and this report adds to the mutational spectrum observed.

A terapia de reposição enzimática pode mudar a frequência de intervenções médicas na mucopolissacaridose tipo I? Um estudo retrospectivo e exploratório / Can enzyme replacement therapy change the frequency of medical interventions in mucopolysaccharidosis type I? An exploratory retrospective study

Introdução: A mucopolissacaridose tipo I (MPS I) é uma doença lisossômica (DL) para a qual está disponível a terapia de reposição enzimática (TRE) com laronidase. Objetivo: caracterizar o efeito da TRE em pacientes com MPS I avaliados por um único centro de referências para DL a partir da análise da frequência de intervenções médicas. Métodos: Estudo retrospectivo e exploratório com comparações pré e pós-intervenção. O número/ano/paciente de consultas, medicamentos usados, internações, cirurgias e exames realizados, foi obtido por meio de revisão de prontuário médico. Essas variáveis foram, então, comparadas entre dois períodos: pré-TRE e pós-TRE. Resultados: Nove pacientes (graves=3, atenuados=6) foram incluídos no estudo. A mediana de idade de início da TRE foi 9 anos e a mediana de duração da TRE foi 4 anos. Em média, os pacientes realizaram 90% das infusões previstas para o período. Somente o número de cirurgias/ano/paciente foi dependente do tempo de doença (p=0,0004) e da gravidade do fenótipo (p=0,014). Com relação às comparações pré e pós-TRE, as variáveis que apresentaram diferença significativa (média do número/ano/paciente) foram: exames (pré-TRE=10,2±2,7; pós-TRE=22,5±2,1; p=0,005) e internações (pré-TRE=0,05±0,04; pós-TRE=0,30±0,11; p=0,013). Conclusão: Nossos dados sugerem que a TRE não alterou a história natural da MPS I em relação aos desfechos analisados. Este achado pode ser devido à idade relativamente avançada de início do tratamento no nosso centro.

Background: Mucopolysaccharidosis type I (MPSI) is a lysosomal disorder (LSD) which can be treated with enzyme replacement therapy (ERT) with laronidase. Aim: To describe the effect of ERT on MPSI patients evaluated at a single referral center for LSD by assessing the frequency of medical interventions. Methods: An exploratory, retrospective study with pre- and post-intervention assessments. We reviewed medical records to collect data on the number of medical appointments/year/patient, medications used, hospital admissions, surgeries, and exams performed. These variables were then compared between the pre- and the post-ERT periods.Results: Nine patients (severe=3; attenuated=6) were included in the study.The median age for the start of ERT was 9 years, and the median time on ERT was 4 years. On average, patients received 90% of the infusions predicted for the study period. Only the number of surgeries/year/patient was found to be dependent on length of disease (p=0.0004) and on severity of phenotype (p=0.014). Regarding pre- and post-ERT comparisons, there was a significant difference (mean number/year/patient in exams (pre-ERT, 10.2±2.7; post-ERT, 22.5±2.1; p=0.005) and hospital admissions (pre-ERT, 0.05±0.04; post-ERT, 0.30±0.11; p=0.013). Conclusion: Our data suggest ERT didn’t alter the natural history of MPSI the outcomes assessed in this study. This may be due to the relatively advanced age of patients when they started treatment at our Center.

Three novel α-L-iduronidase mutations in 10 unrelated Chinese mucopolysaccharidosis type I families

Mucopolysaccharidosis type I (MPS I) arises from a deficiency in the α-L-iduronidase (IDUA) enzyme. Although the clinical spectrum in MPS I patients is continuous, it was possible to recognize 3 phenotypes reflecting the severity of symptoms, viz., the Hurler, Scheie and Hurler/Scheie syndromes. In this study, 10 unrelated Chinese MPS I families (nine Hurler and one Hurler/Scheie) were investigated, and 16 mutant alleles were identified. Three novel mutations in IDUA genes, one missense p.R363H (c.1088G > A) and two splice-site mutations (c.1190-1G > A and c.792+1G > T), were found. Notably, 45 percent (nine out of 20) and 30 percent (six out of 20) of the mutant alleles in the 10 families studied were c.1190-1G > A and c.792+1G > T, respectively. The novel missense mutation p.R363H was transiently expressed in CHO cells, and showed retention of 2.3 percent IDUA activity. Neither p.W402X nor p.Q70X associated with the Hurler phenotype, or even p.R89Q associated with the Scheie phenotype, was found in this group. Finally, it was noted that the Chinese MPS I patients proved to be characterized with a unique set of IDUA gene mutations, not only entirely different from those encountered among Europeans and Americans, but also apparently not even the same as those found in other Asian countries.