About 50% of people of Northeast Asian descent have a dominant mutation in their acetaldehyde dehydrogenase gene, making this enzyme less effective. A similar mutation is found in about 5–10% of blond-haired blue-eyed people of Northern European descent. In these people, acetaldehyde accumulates after drinking alcohol, leading to symptoms of acetaldehyde poisoning, including the characteristic flushing of the skin and increased heart and respiration rates. Other symptoms can include severe abdominal and urinary tract cramping, hot and cold flashes, profuse sweating, and profound malaise. Individuals with deficient acetaldehyde dehydrogenase activity are far less likely to become alcoholics, but seem to be at a greater risk of liver damage, alcohol-induced asthma, and contracting cancers of the oro-pharynx and esophagus due to acetaldehyde overexposure.