Genotypes for the cytochrome P450 enzymes CYP2D6 and CYP2C19 in human longevitY. Role of CYP2D6 and CYP2C19 in longevity.

OBJECTIVE

To test whether some genotypes for CYP2D6 or CYP2C19 could contribute to longevity, we genotyped 241 Danish nonagenarians and centenarians for CYP2D6 and CYP2C19.

METHODS

For CYP2D6 we identified the alleles CYP2D61, CYP2D63 and CYP2D64 with allele-specific polymerase chain reaction (PCR). The CYP2D65 alleles were identified with a long PCR method. For CYP2C19 we identified the alleles CYP2C191, CYP2C192 and CYP2C19*3 with an oligonucleotide ligation assay.

RESULTS

The four alleles for CYP2D6 did not occur in Hardy-Weinberg proportions. The frequency of poor metabolism was slightly higher (10.2%) than expected [7.7%; odds ratio (OR) = 1.36 (0.75-2.40)]. The genotypes for CYP2C19 occur in Hardy-Weinberg proportions. The frequency of poor metabolism (3.8%) was not significantly different from a young control group [3.1%; OR = 1.21 (0.26-5.75)].

CONCLUSION

CYP2D6 could play a role in human longevity due to the lack of Hardy-Weinberg proportions. If CYP2D6 only plays a role in longevity by protecting the poor metabolizers from cancer, we should expect a rise in the frequency in these genotypes in Denmark from 7.7% among young adults to 10-11% among very old people. We found a frequency of poor metabolism of 10.2% in the very old group. CYP2C19 is - due to the occurrence of Hardy-Weinberg proportions and the expected number of poor metabolizers unlikely to contribute to human longevity.