Combined methylmalonic aciduria and homocystinuria

Combined methylmalonic aciduria and homocystinuria is a very rare disease caused by a defect in the synthesis of two cofactors in cobalamin dependent reactions, i.e. adenosylcobalamin and methylcobalamin, active forms of vitamin B12. Early onset disease consists of neurological, hematological and gastrointestinal abnormalities seen in the first year of life and some minor face abnormalities (long philtrum, wide forehead, big and low set ears, long face). Here we report a 4-month-old male with failure to thrive, pancytopenia and neurological disturbance.