Abstract: Objective To investigate the clinical and laboratory profiles of a patient with pustular psoriasis-like skin lesion and cerebral palsy due to biotinidase deficiency. Methods A 5 year and 4 month-old boy with biotinidase deficiency was confirmed by urinary organic acid analysis with gas chromatography/mass spectrometry (GC/MS)and biotinidase activity assay of peripheral blood. His clinical features, laboratory findings, treatment and outcome were studied. Results The boy showed difficulty in taking food after birth, gradually eczema and pustules appeared at the age of 2 months, and generalized erythema and intractable pustular psoriasis-like lesion at the age of 8 months. His intellectual development was normal with retardation of locomotor system. He had muscular dystonia at the age of 6 months. Physical examination showed generalized pustular psoriasis-like lesion, generalized paralysis, hypertonic contracture of extremities, sparseness of scalp hair and severe malnutrition. Routine laboratory tests showed a mild anemia, metabolic acidosis and elevation of plasma creatine phosphokinase. Increased excretion of urinary lactate, pyruvate, 3-OH-propionate, propionylglycine, and 3-methylcrontonylglycine were observed. Biotinidase activity of his peripheral blood was below 0.1 pmol/min/3mm (normal 6.3-9.3 pmol/min/3mm). Biotin (10 mg/day) supplementation led to a dramatic recovery of the skin lesion. After the treatment of rehabilitation, his muscle power was also improved gradually. Conclusions Dermatological and neurological manifestations are the main features of biotinidase deficiency. Early diagnosis and biotin administration can greatly improve the clinical symptoms. Generalized pustular psoriasis-like lesion and cerebral palsy of this boy have improved after the supplementation of biotin, but he may be remained wheelchair-dependent because of delayed diagnosis.

Key words: Biotinidase deficiency, Biotin, Skin manifestations, Neurologic manifestations