Reversal of brain atrophy with biotin treatment in biotinidase deficiency.

Two children with biotinidase deficiency presented with seizures at 2 months of age. The first child had a fluctuating course with continual developmental progress and cessation of seizures despite symptoms of chronic neurologic dysfunction until he was diagnosed at 17 months. The second child had a progressive course with uncontrolled seizures leading to an unresponsive state until she was diagnosed at 6 1/2 months. Neither child had dermatologic symptoms until shortly before the time of diagnosis. Both children improved markedly with biotin treatment. Serial CT-scan and MRI studies of the brain showed a distinct pattern of changes. Shortly after initial presentation, diffuse low attenuation of the white matter was seen followed by progressive marked cerebral atrophy, which was reversed following biotin treatment. Because this is a reversible condition, clinicians should screen for biotinidase deficiency in all children with symptoms of chronic neurologic dysfunction, especially when radiologic findings of low attenuation of the white matter are followed by cerebral atrophy.