Homocystinuria masquerading as vitamin B12 deficiency.

BACKGROUND: Homocystinuria is a rare metabolic disorder characterized by excess homocysteine in the urine. Vitamin B12 deficiency has diverse cutaneous, nervous and ophthalmic manifestations. OBJECTIVE: To report a case of homocystinuria masquerading as vitamin B 12 deficiency. CASE: We hereby are presenting an interesting case of a 4 year old boy who was being treated for Vitamin B 12 deficiency on the basis of history of delayed milestone, abdominal pain and hyperpigmentation of skin which was diagnosed as homocystinuria. CONCLUSION: It is important to carry out ophthalmological examination in every case of megaloblastic anemia if associated with blurring of vision and mental retardation.