ABSTRACT
Biotinidase deficiency (BD) is an inborn metabolic disorder caused by low enzyme activity giving rise to impaired biotin release from dietary proteins. The first symptoms may be seen at first week following birth until 1 year of age. The goal of the therapy is to increase biotin bioavailability by daily 5-20 mg lifelong biotin replacement. Three-month-old girl born to nonconsanguineous parents, admitted to pediatric intensive care with multiple seizures, breathing difficulty and posturing. Blood investigations showed thrombocytopenia and high anion gap metabolic acidosis (HAGMA). Enzyme assay for biotinidase revealed low activities. Urinary organic acid analysis was normal. Enzyme activity is <10% in severe cases whereas between 10-30% in partial deficiency. BD can cause metabolic ketoacidosis, Hyperammonemia and organic Aciduria. BD behaves like immunodeficiency. Rarely bacterial infection can be seen. Treatment is lifelong biotin replacement.