CHARACTERIZATION OF SEIZURES ASSOCIATED WITH BIOTINIDASE DEFICIENCY

Biotinidase deficiency is an autosomal recessively inherited disorder that is often characterized by neurologic abnormalities. We reviewed t he clinical features of 78 symptomatic children, 11 new patients and 6 7 previously reported cases, to determine the frequency, type, age at onset, and the responsiveness of seizures to antiepileptic drugs and b iotin therapy. Forty-three of the 78 (55%) symptomatic children had se izures, and seizures were the presenting symptom in 38% of the enzyme- deficient patients and 70% of those who had had seizures at some time. EEGs were available for 21 of these children. Sixteen were abnormal. The initially abnormal EEGs in eight of 12 infants became normal or im proved with biotin therapy, whereas four continued to be abnormal. In 21 (49%) patients, the seizures were not well controlled with antiepil eptic drugs. Biotin therapy stopped the seizures within 24 hours in 12 of 16 (75%) of those whose seizures were uncontrolled by anticonvulsa nts (five children died prior to diagnosis). Although the metabolic an d cutaneous abnormalities were corrected in the remaining four childre n, they continued to have neurologic abnormalities. Biotinidase defici ency and a trial of biotin (5 to 10 mg) should be considered in infant s less than 1 year of age with poorly controlled seizures, and biotini dase deficiency should be included in the differential diagnosis of an infant or child with unexplained seizures.