The vitamin B-complex are essential water-soluble vitamins, including vitamin B1(thiamine), vitamin B2 (riboflavin ), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), biotin, folic acid and vitamin B12 (cobalamins). A. Vitamin B1 (Thiamine) Vitamin B1 and Thiamine-responsive megaloblastic anemia syndrome In the study of Thiamine-responsive megaloblastic anemia syndrome: a novel mutation at Dr. …