Nutritional vitamin b₁₂ deficiency in infancy: Three case reports and a review of the literature

Three cases of vitamin B₁₂ deficiency that occurred during infancy are presented. These cases appeared to be the result of pre-existing maternal deficiency. All three infants demonstrated evidence of neurodevelopmental delay at presentation, and one had sustained loss of milestones and developed involuntary motor movements. Prior to the initiation of therapy, all three infants were anemic: one was thrombocytopenic and one pancytopenic. In all three cases the hematologic and neurologic abnormalities were corrected with vitamin B₁₂ therapy. The literature is reviewed and discussed with respect to the mechanism of the infants' vitamin B₁₂ deficiency and neurodevelopmental manifestations.