Phenotype, treatment practice and outcome in the cobalamin-dependent remethylation disorders and MTHFR deficiency: Data from the E-HOD registry.

AIM: To explore the clinical presentation, course, treatment and impact of early treatment in patients with remethylation disorders from the European Network and Registry for Homocystinurias and Methylation Defects (E-HOD) international web-based registry. RESULTS: This review comprises 238 patients (cobalamin C defect n = 161; methylenetetrahydrofolate reductase deficiency n = 50; cobalamin G defect n = 11; cobalamin E defect n = 10; cobalamin D defect n = 5; and cobalamin J defect n = 1) from 47 centres for whom the E-HOD registry includes, as a minimum, data on medical history and enrolment visit. The duration of observation was 127 patient years. In 181 clinically diagnosed patients, the median age at presentation was 30 days (range 1 day to 42 years) and the median age at diagnosis was 3.7 months (range 3 days to 56 years). Seventy-five percent of pre-clinically diagnosed patients with cobalamin C disease became symptomatic within the first 15 days of life. Total homocysteine (tHcy), amino acids and urinary methylmalonic acid (MMA) were the most frequently assessed disease markers; confirmatory diagnostics were mainly molecular genetic studies. Remethylation disorders are multisystem diseases dominated by neurological and eye disease and failure to thrive. In this cohort, mortality, thromboembolic, psychiatric and renal disease were rarer than reported elsewhere. Early treatment correlates with lower overall morbidity but is less effective in preventing eye disease and cognitive impairment. The wide variation in treatment hampers the evaluation of particular therapeutic modalities. CONCLUSION: Treatment improves the clinical course of remethylation disorders and reduces morbidity, especially if started early, but neurocognitive and eye symptoms are less responsive. Current treatment is highly variable. This study has the inevitable limitations of a retrospective, registry-based design.

Clinical response to long term enzyme replacement treatment in children, adolescent and adult patients with Hunter syndrome.

BACKGROUND AND OBJECTIVE: Since enzyme replacement treatment (ERT) with idursulfase is available for Hunter syndrome (HS; mucopolysaccharidosis type II), for the first time, disease progression can be limited and organ damage reduced or prevented. PATIENTS AND METHODS: We described retrospectively the clinical evolution of eight HS males, treated with ERT and followed in routine clinical practice in Hospital Infantil La Fe (Valencia, Spain). RESULTS: We studied three children, three adolescents and two adults. Time from diagnosis to ERT ranged from 13.7 to 0.2 years, and duration of ERT ranged from 24 to 77.1 months. From the start of ERT, weight and height increased in children and adolescents and remained stable in adults. Glycosaminoglycans (GAG) decreased in all patients; in patient 5 (aged 23 years), we observed the highest reduction (86%) with recovery of carpal tunnel syndrome, splenomegaly and a decrease in nocturnal oxygen dependence. CONCLUSION: Our results show that ERT improve respiratory impairment and organomegalies and decrease GAGs levels in all patients including children, adolescent and adults. While cardiac manifestations and facial features stabilized, responses in other parameters were heterogeneous.