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

Clinical manifestations and treatment of mucopolysaccharidosis type I patients in Latin America as compared with the rest of the world.

BACKGROUND: Mucopolysaccharidosis I (MPS I) comprises a spectrum of clinical manifestations and is divided into three phenotypes reflecting clinical severity: Hurler, Hurler-Scheie, and Scheie syndromes. There may be important variations in clinical manifestations of this genetic disease in patients residing in different regions of the world. METHODS: Using data from the MPS I Registry (as of September 2009), we evaluated patients from Latin America (n = 118) compared with patients from the rest of the world [ROW (n = 727)]. RESULTS: Phenotype distribution differed among patients in Latin America compared to ROW (Hurler 31 vs. 62%, Hurler-Scheie 36 vs. 21%, Scheie 10 vs. 11%, and unknown 22 vs. 6%). The frequency of certain symptoms, such as cardiac valve abnormalities, sleep impairment, and joint contractures, also differed between Latin America and ROW for some phenotypes. Median age at MPS I diagnosis was earlier in the ROW than Latin America for all phenotypes, and age at first treatment for Hurler and Hurler-Scheie patients was also earlier in the ROW. Hurler patients in Latin America showed a gap of 3.1 years between median ages of diagnosis and first treatment compared to only 0.5 years in the ROW. Treatment allocation in Latin America compared to ROW was as follows: enzyme replacement therapy (ERT) only, 80 vs. 45%; hematopoietic stem cell transplantation (HSCT) only, 0.9 vs. 27%; both ERT and HSCT, 0 vs. 16%; and neither treatment, 19 vs. 13%. CONCLUSION: These data highlight important differences in MPS I patients between Latin America and ROW in terms of phenotypic distribution, clinical manifestations, and treatment practices.

Characterization of surgical procedures in patients with mucopolysaccharidosis type I: findings from the MPS I Registry.

OBJECTIVE: To clarify the extent and chronology of surgical burden in relation to symptom onset and diagnosis in patients with mucopolysaccharidosis I (MPS I) as reported in the MPS I Registry, an international observational database. STUDY DESIGN: Analysis of surgical data from 544 patients enrolled in the MPS I Registry. Among all patients with at least 1 reported surgery, the number and frequency of procedures, and age at procedure, diagnosis, and symptom onset were collected overall, by patient, and by reported phenotype (Hurler, Hurler-Scheie, Scheie). RESULTS: Overall and by phenotype, approximately 75% of patients in the MPS I Registry reported at least 1 surgery. The most common were myringotomies and related procedures, hernia repair, adenoidectomy/tonsillectomy, and carpal-tunnel release. Median age at first surgery was <5 years. A median of 3 to 4 surgeries was reported per patient. By age 1.5, 4, and 10 years, respectively, 22%, 44%, and 54% of patients reported > or = 2 surgeries. At least 1 surgery preceded diagnosis in 36%, 46%, and 63% of patients with Hurler, Hurler-Scheie, and Scheie, respectively. CONCLUSIONS: Pediatricians and pediatric surgeons need to be aware of the surgical burden of MPS I and be alert to its presenting signs and symptoms in children scheduled for surgery.

[Mucopolysaccharidosis type I in the Cuban population]. / Mucopolisacaridosis tipo I en la población cubana.

INTRODUCTION: Of all the innate errors of the metabolism, the mucopolysaccharidoses (MPS), a kind of lysosomal disease, are especially significant because of the serious clinical features they give rise to and the therapeutic difficulties they entail. Diagnosis of the index case is essential so that families can gain access to the preventive benefits of genetic counselling. To date, seven types of MPS and 11 enzyme deficiencies have been described. AIMS: Patients with a clinical diagnosis that leads the clinician to suspect they may be suffering from some type of MPS are referred to the Institute of Neurology and Neurosurgery to determine the possible enzyme deficiencies that will provide us with the key to a successful diagnosis. PATIENTS AND METHODS: A total of 588 patients who were clinically suspected of suffering from MPS, in whom 1,502 enzyme analyses were performed in order to classify the type of MPS they were suffering from. The MPS under examination are MPS I, MPS IIIB, MPS IVB, MPS VI and MPS VII. RESULTS: MPS I, or alpha-L-iduronidase deficiency, is the most commonly found with 23 cases (4.08% of the patients studied); 13 were females and the other 10 were males. Of the 23 cases, 10 presented the severe Hurler phenotype with mental retardation, five had the Scheie phenotype with preserved intelligence and eight displayed the intermediate Hurler-Scheie phenotype. Diagnosis was reached before the end of the first year in eight patients, between 1 and 5 years in nine of them and between 6 and 10 years in two cases. Enzyme activity in leucocytes was significantly lower in patients as compared to a control group and with respect to the parents (heterozygotes), and even comparing these to the control group, with a slight and expected overlap. CONCLUSION: The biochemical methodology used allows us, then, to reach a sure biochemical diagnosis and to offer the families the benefits of genetic counselling.

Follow-up of nine patients with Hurler syndrome after bone marrow transplantation.

We report our experience in nine patients with Hurler syndrome (six with a severe and three with an intermediate phenotype) who successfully engrafted after bone marrow transplantation. The donor was a human leukocyte antigen-identical sibling in six cases, the human leukocyte antigen-identical father in one case, and an unrelated donor in two cases. One patient with Hurler syndrome and an intermediate phenotype received two successive grafts from the same donor. There was a beneficial effect of bone marrow transplantation on visceral features (hepatosplenomegaly, obstruction of the upper airway, and coarse facies); however, dysostosis multiplex worsened. All patients but one required surgery for carpal tunnel syndrome. Visual acuity was low because of corneal clouding, and two patients had glaucoma several years after the graft. Five patients had normal hearing before the graft that remained normal, and four had hearing impairment that improved. All patients had learning difficulties, but none had severe mental retardation (IQ ranging from 75 to 103). The follow-up of patients with severe Hurler syndrome engrafted for more than 10 years emphasizes the limits and benefits of bone marrow transplantation.