Authors from La Jolla, USA and Florence, Italy report the case of a boy who was first admitted to hospital at 5 years of age because of acute somnolence, alopecia, keratoconjunctivitis and perioral stomatitis associated with lactic acidaemia. At 6 years of age he had grand mal seizures and ataxia and at 7 years he was admitted in coma. The diagnosis of multiple carboxylase deficiency due to biotinidase deficiency was then suspected and treatment with biotin 10 mg p.o.q.d. was started after urine for organic acid analysis was collected. The clinical response was dramatic. Coma and acidosis resolved within a few days. No further seizures occurred. The skin gradually returned to normal and hair, eyebrows and eyelashes regenerated. Ataxia responded after a few weeks but optic atrophy and nerve deafness persisted.
This patient’s history began at 6 months of age with seizures. He had multiple generalized tonic-clonic seizures without fever, apparently unresponsive to medication. His subsequent motor development was slow; he sat at 1 year and walked at 2 years. The EEG showed a diffuse abnormality with poorly localized spike foci. Alopecia, a characteristic sign of biotinidase deficiency, did not develop until after 2 years of age. 
COMMENT: Biotin-related genetically determined disorders are of two types: 1. young infantile or neonatal disease caused by deficiency of holocarboxylase synthetase and 2. late infantile disease due to biotinidase deficiency. Neurological manifestations are prominent in the late-onset group and seizures may precede the cutaneous eruption and loss of hair.
Having encountered one such patient who presented at the age of 5 years with ataxia and seizures refractory to medications (In Nutrition, Diet, and your Child’s Behavior. Charles C Thomas, Springfield, 1986.), I now make it a practice to prescribe biotin 10 mg daily as a therapeutic test when this diagnosis is suspected. Treatment reverses the organic aciduria so that a urine collection for analysis should precede administration of the vitamin. A dramatic response to a vitamin in a single daily dose is certainly an improvement over long-term anticonvulsant drug therapy with its attendant potential side-effects. Supplies of biotin from Roche Labs are available only for research at present.