Pernicious Anemia (Vitamin B-12 Deficiency): Pernicious anemia (vitamin B-12 deficiency) is a type of anemia that is a result of the body's inability to absorb vitamin B-12 into the gastrointestinal tract. Common symptoms are fatigue and shortness of breath. Causes of pernicious anemia can be attributed to autoimmune diseases such as thyroid disorders, vitiligo, celiac disease, Crohn's disease, and infection and poor nutrition. Treatment for pernicious anemia is generally with life-long vitamin B-12 injections.