Abstract
Biotin is a water-soluble vitamin and a cofactor of several types of carboxylases. Insufficient intake of biotin and a congenital deficiency of enzymes that are required for biotin to act in the cell cause clinical symptoms called multiple carboxylase deficiency (MCD). In recent years, there have been several reports of infants with food allergy and/or atopic eczema who developed MCD after being fed with peptide formula. We investigated the incidence of nutritional biotin deficiency and congenital enzyme deficiency in Japan. For the estimated incidence of biotin deficiency, there were at least 70 cases in the last 10 years. Since the first diagnosis of holocarboxylase synthetase deficiency (HCSD) in 1982, HCSD and biotinidase deficiency were confirmed in 28 and 2 cases, respectively. These data suggest that the incidence of congenital enzyme deficiency is about 1 case per year. Biotin-responsive basal ganglia disease (BBGD) is an encephalopathy of children whose symptoms are ameliorated by biotin administration. Mutations in the SLC19A3 gene were identified in the patients. SLC19A3 shows transporter activity for thiamin but not for biotin. The mechanism of biotin-responsiveness in BBGD is not yet elucidated. Further, patients with Leigh-like syndromes have been shown to have mutations in this gene. Currently, the relationship between biotin and SLC19A3 is largely unknown.
