[Biotinidase deficiency--a progressive metabolic disease in children with seizures and ataxia].

Biotinidase deficiency is the primary biochemical defect in late-onset multiple carboxylase deficiency and an autosomal recessive disorder and characterized by seizures, ataxia, alopecia and skin rash. We describe a colorimetric semiquantitative method for screening for biotinidase activity from dried samples of whole blood spotted on filter papers. The administration of biotin to affected children can be a lifesaving procedure and can prevent irreversible neurologic damage.