CYP2D6 polymorphism screening in a selected population of Spain (La Alpujarra): no effect of geographical isolation.

BACKGROUND There is growing interest in the CYP2D6 gene because of its key role in the metabolism of numerous commonly used drugs. AIM We compared the frequency of the most frequent null CYP2D6 alleles (CYP2D6*3, CYP2D6*4,CYP2D6*5, CYP2D6*6, CYP2D6*7 and CYP2D6*8) between individuals from the Spanish population and from La Alpujarra. SUBJECTS AND METHODS The present study comprises Spanish cohort (n = 185) and from La Alpujarra (n = 104). The latter is a small mountainous region of Spain that shows a remarkable degree of geographical and cultural isolation. We genotyped six polymorphisms in the coding region of the CYP2D6 gene, i.e. five single nucleotide polymorphisms (SNP) (CYP2D6*3, CYP2D6*4, CYP2D6*6,CYP2D6*7 and CYP2D6*8) and one deletion (CYP2D6*5). RESULTS No significant differences were observed between groups in allelic and genotype distributions of the aforementioned variants. The total frequency of functional alleles was comparable between the two groups (79% and 81.3% in controls and La Alpujarra, respectively). CONCLUSION Despite demographic and cultural isolation in La Alpujarra, the distribution of CYP2D6 polymorphisms in inhabitants of this area is similar to that reported in the rest of Spain. At present, there seems to be little allele heterogeneity in CYP2D6 amongst different European populations (e.g., amongst different Spanish populations) that have shown diversity in other loci.