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Overview Edit

Redrashonbackalcoholallergy

Alcohol flushing on the back. Source: http://www.redfacefromalcohol.com/picturesofallergicreactiontoalcohol.htm

Alcohol flush reaction is also known as sensitivity to alcohol, alcohol intolerance, Asian flush, and Asian glow due to the majority of Asians displaying flushing symptoms as compared to to other ethnicities. Individuals with alcohol flush reaction turn red in the face and throughout the entire body after as little as one drink.

Symptoms according to the Mayo Clinic may include: hives, facial redness, runny nose, headache, low blood pressure, and nausea.

This condition has been associated with decreased risk of alcoholism and increased risk of esophageal cancer for those who choose to drink despite the symptoms. This increased risk was found in east Asians in

Typicalredlegsnoredfaceformula

Alcohol flushing on legs. Source: http://www.redfacefromalcohol.com/picturesofallergicreactiontoalcohol.htm

Causes Edit

This type of reaction is caused by a deficiency in aldehyde dehydrogenase, which is an important enzyme in the catabolism of alcohol. Without this enzyme, aldehyde accumulates, which results in the flushing effect after consuming alcohol. Those who are deficient in the enzyme are less prone to alcoholism and a drug that mimics these effects (disulfiram) are used to treat alcoholism.

Genetics

Ethanol metabolism

Ethanol metabolism to aldehyde and acetic acid. Source: http://en.wikipedia.org/wiki/Alcohol_flush_reaction

Alcohol flush reaction is determined by the genotype on two specific genes, which are ALDH2 and ADH1B. 23andMe genotypes the SNP at ALDH2. The possible genotypes at the ALDH2 are AA, AG and GG. The AA genotype leads to a high probability to extreme flushing due to alcohol due to lack of functional copies of ALDH2. This genotype is highly unlikely to become addicted to alcohol. The AG genotype contains one functional copy of ALDH2 and leads to high likelihood of moderate flushing. These individuals are less likely to become alcoholic than GG individuals, but more likely than AA individuals. The GG genotype contains both functional copies of ALDH2 and likely flushes little or none at all. These individuals are more likely to become alcoholic because they have little of the unpleasant side effects.

ALDH2 gene codes for the aldehyde dehydrogenase protein, which is responsible for converting acetaldehyde (highly toxic) to acetic acid (also known as vinegar and nontoxic). An SNP that contains "A" contains a gene, which encodes for an inactive enzyme that fails to make acetaldehyde into a less toxic compound. This effects alcohol metabolism and having an A in the genotype means that ethanol will be eliminated from the body much more slowly than it would in those individuals that have have the GG genotype. The ADH1B gene is a variant of ALDH2 that encodes for a protein in the family of aldehyde dehydrogenase. There are multiple genes and variants of the ALDH2 gene.

What This Means for John Burke Edit

Dr. Burke has the GG genotype, which means he has little to no flushing and is more prone to alcoholism. He should only drink in moderation and avoid excessive amounts of alcohol because too much will still cause damage to his body even though his body is fast at metabolizing alcohol. It would be recommended that he monitor his alcohol intake because his body won't display the toxic symptoms that those with AA and AG genotypes will.

Dr. Burke does not have increased risk for esophageal cancer due to alcohol intake because he does not have this condition.

References Edit

1. 23andme article: Alcohol Flush Reaction Overview. Date accessed: Dec 6, 2014.

2. Wikipedia article: Alcohol Flush Reaction. Date accessed: Dec 6, 2014.

3. Mayo Clinic - Alcohol Intolerance. Date accessed: Dec 6, 2014.

4. Wikipedia article: ADH1B. Date accessed: Dec 6, 2014.

5. "Esophageal Cancer and the 'Asian Glow'" DUJS Online. Dartmouth College, 21 Nov. 2009. Web. 06 Dec. 2014.