Answer to hypotonia:: A simple hemogram

A 1-year-old boy with weight loss, decreased activity, and psychomotor regression is presented. He was subjected to an extremely detailed evaluation, including electroencephalography (EEG) and magnetic resonance imaging (MRI), until a simple hemogram. in our center revealed that he had macrocytic anemia with megaloblastic changes in the bone marrow. His history revealed that he had been exclusively breast-fed by his vegetarian mother. Further investigations showed low serum vitamin B-12 concentration, methylmalonic aciduria, and homocysteinemia, indicating that the macrocytic anemia was due to vitamin B-12 deficiency. This boy represents a case of macrocytic anemia and hypotonia owing to vitamin B-12 deficiency that developed because of exclusive breast-feeding by a vegetarian mother.