Vitamin B12 deficiency in children: a treatable cause of neurodevelopmental delay.

Vitamin B12 deficiency in children can rarely cause neurologic manifestations. In this series, 14 pediatric cases (median age 11 months) have been described in whom association of vitamin B12 deficiency with developmental delay or regression was observed. Severe to profound delay was present in 8 (57%) patients. All the patients were exclusively or predominantly breast-fed and 10 of 12 mothers had low serum vitamin B12 levels. Three to 6 months after treatment, a mean gain of development quotient of 38.8 points was seen in 7 follow-ups. In settings with a high prevalence of vitamin B12 deficiency, this association should be actively searched for.