Infantile tremor syndrome -- down but not out.

Retrospective chart review of 21 infants with infantile tremor syndrome for vitamin B12 deficiency showed low serum vitamin B12 levels in 8/16 (50%). Of the eight infants with normal levels, six had received vitamin B12 before referral. Macrocytosis and low maternal serum B12 was found in 12 and seven cases each. Treatment with vitamin B12 alone produced rapid recovery.