Cobalamin deficiency and related disorders in infancy and childhood

This review discusses recent knowledge of the many causes of cobalamin deficiency in infancy and childhood. These causes are classified as (1) inadequate intake, (2) inadequate absorption and (3) inadequate utilisation. It is emphasized that the ‘serum B12’ may be normal in cases of the grossest derangement of B12 metabolism, with extreme functional deficiency of this group of vitamins (the cobalamins). For completeness, causes of folate deficiency and other conditions causing megaloblastosis in children are also briefly outlined.