one of the diverse group of disorders that cause pernicious anemia in childhood , juvenile pernicious anemia , has been characterized by normal acid secretion , normal gastric mucosal histology , adequate intestinal absorption of cobalamin in the presence of exogenous gastric intrinsic factor ( if ) , but the inadequate `` '' production '' '' of if from birth .
C0002892
pernicious anemia
C0042845
cobalamin