Biochemical and genetic studies of Caucasian subjects with ethanol-induced flushing reaction

The prevalence of ethanol-induced flushing was investigated in three different Caucasian student populations, namely Irish, Belgian and English. Approximately 45% of all female subjects reported a flushing reaction, while 33%, 17% and 9%, respectively, of male students reported this reaction. There was a high familial incidence of flushing in all groups, suggesting that a specific gene defect might be involved. Our previous investigations had inferred normal ALDH2 in such affected individuals, but low activities of erythrocyte ALDH1.(1) Since the principal role of this cytosolic enzyme may be in the metabolism of biogenic amines, serotonin levels in platelet-rich plasma and urinary adrenaline, noradrenaline and dopamine were assayed in affected individuals after an oral ethanol challenge. No consistent pattern was evident for any of these parameters in any of the subjects at the time intervals investigated. Genotyping for ADH31 and ADH32 showed a higher frequency for ADH3(1) , 58%, than ADH3(2) , 42%. This is comparable to the Caucasian controls and to our previously published data.