[Congenital malabsorption of vitamin B12 (Imerslund's syndrome) in a premature girl with Down's syndrome (author's transl)].

A baby girl, born prematurely and with Down's syndrome, is hospitalized at the age of 51 days for a megaloblastic anemia. The anemia was caused by a selective malabsorption of vitamin B12 (Imerslund's syndrome), even in presence of intrinsic factor. The pathogenesis of different causes of vitamin B12 deficiency is discussed and the favourable development of this case after four years of treatment is shown.