Pernicious anemia may result from
- rupture of red blood cells due to parasites.
- abnormal production of hemoglobin due to genetic defect.
- the lack of vitamin B12 in diet or deficiency of intrinsic factor needed to absorb B12.
- excessive bleeding.
- the absent or depressed synthesis of globin chains.
Answer: the lack of vitamin B12 in diet or deficiency of intrinsic factor needed to absorb B12.