rs671

rs671 is a classic SNP, well known in a sense through the phenomena known as the "alcohol flush", also known as the "Asian Flush" or "Asian blush", in which certain individuals, often of Asian descent, have their face, neck and sometimes shoulders turn red after drinking alcohol. The rs671(A) allele of the ALDH2 gene is the culprit, in that it encodes a form of the aldehyde dehydrogenase 2 protein that is defective at metabolizing alcohol. This allele is known as the ALDH*2 form, and individuals possessing either one or two copies of it show alcohol-related sensitivity responses including facial flushing, and severe hangovers (and hence they are usually not regular drinkers). Perhaps not surprisingly they appear to suffer less from alcoholism and alcohol-related liver disease. PMID 511165, PMID 16046871 Disulfiram (Antabuse) is probably an ineffective treatment for alcohol dependence in people who have the Asian Flush. Tests for the alcohol flush reaction at deCODEme are based on rs671. 23andMe blog carriers of the A allele are prone to esophageal cancer, which is also known as upper aerodigestive tract (UAT) cancer, due to acetaldehyde from smoking. Alcohol Consumption, Smoking and Risk of Esophageal Cancer

A;A

People with this genotype will experience the asian flush, a redness in the face when drinking alcohol. Unable to break down acetaldehyde, a toxic byproduct of alcohol and cigarette smoke. As a result, you are likely to have greatly increased odds of esophageal cancer, especially if you drink or smoke. It also causes worse hangovers. On the bright side, that makes you much less likely to become an alcoholic. If you become an alcoholic anyway, disulfiram (Antabuse) will not be an effective treatment.

A;G

People with this genotype will experience the asian flush, a redness in the face when drinking alcohol. They can only break down acetaldehyde at half the normal speed, a toxic byproduct of alcohol and cigarette smoke. As a result, you are likely to have increased odds of esophageal cancer, especially if you drink or smoke. It also causes worse hangovers. On the bright side, that makes you less likely to become an alcoholic. If you become an alcoholic anyway, disulfiram (Antabuse) probably won't be an effective treatment.

G;G

Two working copies of Aldehyde Dehydrogenase (ALDH2) mean you won't turn bright red when you drink alcohol, unlike most Asians. After your body turns alcohol into the dangerous acetaldehyde, this gene quickly turns the acetaldehyde into vinegar. It also stops the acetaldehyde in cigarettes from causing Esophageal Cancer. It reduces hangovers compared to Asians, but less hangovers and flushing obviously increases the risk of alcoholism. Alcoholism can be treated effectively with the drug Disulfiram (Antabuse) which would stop this gene from working and cause the Asian flush in non-Asians. PMC2659709 ncbi.nlm.nih.gov"AALDH2-deficient individuals are at much higher risk of esophageal cancer (specifically squamous cell carcinoma) from alcohol consumption than individuals with fully active ALDH2. This is particularly unfortunate as esophageal cancer is one of the deadliest cancers worldwide, with five-year survival rates of 15.6% in the United States, 12.3% in Europe, and 31.6% in Japan"