[Biotidinase deficiency: a disease with neurologic and cutaneous expression susceptible to biotin]

The authors report 2 familial cases of biotin deficiency. The first neurological signs appeared at the age of 2 years in a boy. The diagnosis was established in his sister in the neonatal period. A review of 41 published cases summarizes the neurologic signs (seizures, ataxia, hypotonia and later, developmental delay and deafness) and the cutaneous signs (rash, alopecia). An early treatment with biotin cures or prevents the clinical signs of the disease in most cases.