[Epidemiological study of the metabolic diseases with homocystinuria in Spain].

OBJECTIVES: To determine the prevalence of homocystinuria in Spain and to establish the measures and mechanisms to ensure its prevention, diagnosis and treatment.

MATERIAL AND METHODS: A national cross-sectional survey was conducted by means of a questionnaire sent to 35 hospitals in which children and adult patients are treated.

RESULTS: Using the questionnaires submitted by 25 physicians from 16 centres, 75 patients were identified: 41 transsulphuration defects (one deceased), 27 remethylation (six deaths) and 7 without a syndromic diagnosis. The age at diagnosis varied widely, and 18 cases had more than one sibling affected. The more severe clinical manifestations involved the patients with remethylation defects. There was a high percentage of cognitive impairment, followed by lens diseases. Almost half of the patients had neurological disorders. There was increased vascular involvement in CBS-deficient adults. The therapeutic options most used were, folic acid, hydroxycobalamin and betaine.

CONCLUSIONS: In view of these results and especially the small number of CBS deficiencies detected, we conclude that there is a need to introduce newborn screening for classical homocystinuria and ensure implementation of an appropriate diagnostic workup in all patients at risk.