A functional locus in ALDH2, rs671, explains a significant proportion of the genetic and phenotypic variation in this Chinese male sample. The role of this variant in the inability to metabolize ethanol fully, leading to nausea and other adverse consequences in addition to the appearance of facial flushing, has been well established and suggests a mechanism of action by which the frequency and volume of alcohol consumption is reduced. Due to overall low consumption of alcohol – which might be considered “environmental censoring” of phenotypic data – we are unable to draw conclusions about AD risk in the females in our sample. As this is a family-based sample ascertained on the basis of AD probands and these families are drawn from a relatively isolated region of China, it should be noted thatthe variation explained may not be generalizable to other populations in China and certainly will not be applicable to other populations where rs671 shows significantly different allele frequencies.
