Spinal cord demyelination associated with biotinidase deficiency in 3 Chinese patients

Biotinidase deficiency is a treatable cause of severe neurological disorders and skin problems. Spinal cord impairment is a rare complication of this disease and is commonly unrecognized. The authors encountered 3 Chinese patients with progressive spinal cord demyelination associated with biotinidase deficiency. Case 1 exhibited fatigue, proximal muscular weakness, and hypotonic paraplegia from the age of 7 years 4 months. Demyelination of cervical and thoracic cord was evident on magnetic resonance imaging (MRI). Case 2 developed visual impairment, blepharoconjunctivitis, and optic nerve atrophy from 5 years of age, which combined with progressive hypertonic paralysis, ataxia, and alopecia from the age of 7 years. His spinal MRI T2-weighted sequence revealed an extensive hyperintense lesion involving the cervical spinal cord C(2) to C(4). Bilateral optic nerves were significantly thick. In case 3, intercurrent wheezing, tachypnea, dyspnea, and lethargy occurred from the age of 1 year. Medulla and upper cervical spine edema and demyelination were found on MRI. Markedly elevated urine organic acids and decreased blood biotinidase activities were observed in the 3 patients. Biotin supplementation led to a dramatic improvement of clinical symptoms in 3 patients. The findings indicate that biotinidase deficiency should be considered in the differential diagnosis of unexplained spinal cord demyelination because prompt diagnosis and treatment with biotin may enable an excellent recovery.