More on What Is Alzheimer's Disease Apolipoprotein B-100. Mutations of this gene result in LDL staying in the blood for longer than normal, leading to very high LDL levels. In people of Western European descent, one person in 500 has a mutation in the Apo B-100 gene. In almost all human tissues, normal cellular processes generate a waste product called homocysteine. Homocysteine is then cleared from the blood and recycled.
Doctors treat hyperhomocystinemia with folate supplements.
Cystathione B-synthase, or CBS , is another enzyme involved in homocysteine metabolism. People who have mutations in both alleles of the CBS gene have a condition called homocystinuria, in which blood levels of homocysteine are so high that it can be detected in the urine. Even though ACE has been studied extensively, many of the investigators have reported conflicting results. However, these studies involved small numbers of people and have yet to be repeated with larger groups. Certain mutations in the apo A1 gene result in low apo A1 levels, low HDL levels, early heart attacks, and strokes.