deCODE Complete
Analyzes risk factors for more than fifty common diseases and several traits, including all of those for which deCODEhealth offers individual disease tests. deCODE Complete focuses on medical conditions that can either be better prevented through altered lifestyle or that have better treatment outcomes if detected early. It is the most comprehensive genetic scan available for evaluating risk of common diseases. It is not generally reimbursable.
Diseases and conditions covered by the deCODE Complete Scan:
Abdominal Aortic Aneurysm, ABO Blood Types, Age Related Macular Degeneration, Alcohol Flush Reaction, Alzheimer’s Disease, Asthma, Atrial Fibrillation, Basal Cell Carcinoma, Bitter Taste Perception, Bladder Cancer, Brain Aneurysm, Brain Cancer-Glioma, Breast Cancer, Celiac Disease, Chronic Kidney Disease, Chronic Lymphocytic Leukemia, Chronic Obstructive Pulmonary Disease, Clopidogrel Response, Colorectal Cancer, Crohn’s Disease, Essential Tremor, Exfoliation Glaucoma, Eye Color, Gallstones, Gout, Heart Attack, Hemochromatosis, Hypertension, Kidney Stones, Lactose Intolerance, Lung Cancer, Male Pattern Baldness, Multiple Sclerosis, Nicotine Dependence, Obesity, Ovarian Cancer, Pancreatic Cancer, Peripheral Arterial Disease, Prostate Cancer, Psoriasis, Restless Legs Syndrome, Rheumatoid Arthritis, Statin Induced Myopathy, Systemic Lupus Erythematosus, Testicular Cancer, Thyroid Cancer, Type 1 Diabetes, Type 2 Diabetes, Ulcerative Colitis, Venous Thromboembolism, Warfarin Metabolism.
Alcohol Flush Reaction
Alcohol Flush Reaction is mainly due to the inheritance of one or two copies of the ALDH2*2 genetic variant.
The deCODE Complete Scan analyzes your patients’ DNA for this variant and provides you with a personalized interpretation of their risk for Alcohol Flush Reaction.
People with alcohol flush reaction have a genetic variant affecting how their bodies break down alcohol – deCODEhealth can identify the existence of this variant or not
An unpleasant response to drinking alcohol
Some people experience an unpleasant reaction to drinking even a slight amount of alcohol. Their face turns red, and sometimes they also have signs of drowsiness, increased heart rate, nausea, and symptoms of reduced blood pressure. This reaction to alcohol is most commonly seen in individuals of East Asian ancestry, which is why it is sometimes referred to as the "Asian Flush".
Occurs when the body cannot break down ingested alcohol
Alcohol is toxic to human bodies. In people who do not experience alcohol flush reaction, alcohol is broken down (metabolized) in the liver into substances which can be either used or excreted by the body. This breakdown occurs in several steps. First the enzyme alcohol dehydrogenase (ADH) converts alcohol to acetaldehyde. Acetaldehyde is a substance even more toxic to the body than alcohol and contributes largely to the adverse effects of alcohol generally known as a “hangover”. Second, acetaldehyde is broken down into the harmless acetic acid (or vinegar) by another enzyme called aldehyde dehydrogenase-2 (ALDH2). A third enzyme finally breaks the acetic acid into fat, carbon dioxide, and water. The impaired function of any of these critical enzymes disrupts alcohol metabolism, leading to varying degrees of discomfort depending on the amount of alcohol ingested and which enzyme is affected.
Alcoholic beverages are often a complex mixture of grape, yeast, hop, barley or wheat-derived substances and preservatives. The symptoms associated with alcohol flush reaction can also be experienced due to sensitivity to these substances in alcoholic beverages or medications that can interact with alcohol in this way.
A known genetic variant is the major cause for alcohol flush reaction
Alcohol flush reaction is largely due to a genetic variant that affects one of the enzymes responsible for breaking down (metabolizing) alcohol. This genetic variant is found in the ALDH2 gene and is known as the ALDH2*2 allele. The ALDH2 gene regulates the production of the enzyme aldehyde dehydrogenase 2 that has the role of transforming acetaldehyde into acetic acid. The ALDH2*2 allele is dominant. This means that even one copy of it interferes with the formation of a fully functional ALDH2 enzyme, with the result that acetaldehyde cannot be broken down and builds up in the body when drinking alcohol, leading to the symptoms described above.
The ALDH2*2 variant is common in individuals of East Asian descent (45-50%), but is extremely rare in most non-Asian populations.
deCODEhealth can assess your patients’ genetic risk for alcohol flush reaction
The deCODE Complete Scan identifies the sequence variant (rs671) in the ALDH2 gene on chromosome 12 and gives an interpretation of the associated genetic risk for alcohol flush reaction. It does not at this time identify the sequence variants associated with the defective ADH enzyme in the first step of alcohol breakdown.
The benefits to having alcohol flush reaction
Having the genetic variant(s) predisposing individuals to alcohol intolerance also has an advantage; these individuals may be protected against developing alcoholism, at least partly due to the fact that they often choose to avoid alcoholic beverages altogether. Studies have indeed shown that people of Asian descent, as a whole, have lower rates of alcohol dependence compared with other ethnic groups. In fact, the knowledge behind the alcohol flush reaction has been utilized in therapeutics for alcoholism. Doctors sometimes prescribe alcoholics with a drug called disulfiram which essentially mirrors the ALDH2*2 effect (inhibits the ALDH2 enzyme) and hence discourages use and abuse of alcohol.
More information
If concerned about alcohol flush reaction, their doctor is their best resource. Additional information can be found on these web sites:
- National Institute on Alcohol Abuse and Alcoholism (NIAAA)
- MedlinePlus – Trusted Health Information for You
Scientific references
- Chen, C.C., Lu, R.B., Chen, Y.C., Wang, M.F., Chang, Y.C., Li, T.K., & Yin, S.J. . Interaction between the functional polymorphisms of the alcohol-metabolism genes in protection against alcoholism.The American Journal of Human Genetics, 65(3), 795-807.
- Edenberg, H.J. . The genetics of alcohol metabolism. Alcohol Research & Health, 30(1), 5-13.
- Eng, M.Y., Luczak, S.E., & Wall, T.L. . ALDH2, ADH1B, and ADH1C genotypes in asians: A literature review. Alcohol Research & Health,30(1), 22-27.
- Weathermon, R. & Crabb, D.W. . Alcohol and medication interactions. Alcohol Research & Health, 23(1), 40-54.
This content was last reviewed on February 16, 2012.