PERNICIOUS anemia is essentially a disease of adults,1 rarely seen under the age of 30 and beginning more commonly during the fifth decade. It is characterized by a macrocytic anemia, a related degeneration of the mucosa of parts of the gastrointestinal tract with a resultant complete achlorhydria and frequently a related degeneration of the central nervous system. It is primarily a deficiency disease, the gastrointestinal tract failing to yield the intrinsic factor, which unites with the extrinsic factor, from food, to form the erythrocyte maturation factor. This lack results in a maturation defect, an arrest of erythropoiesis at the megaloblastic level. There may be spontaneous remissions and relapses in the disease. Continuous treatment with preformed maturation factor results in reticulosis and in correction of the anemia but does not abolish the achlorhydria or bring about a regeneration of the gastric mucosa.
Closely related disorders exist which result from other