Abstract
AIM: To compare the frequency of alleles and genotypes in brain-derived neurotrophic factor (BDNF) val66met polymorphism in ethnically homogenous Caucasian (from Croatia) and ethnically homogenous Asian (from South Korea) healthy participants, as inter-population differences in BDNF val66met may be responsible for the divergent findings in genetic and association studies. METHODS: BDNF val66met was genotyped in 800 (556 Croatian and 244 Korean) healthy participants. Frequencies of alleles and genotypes were evaluated using a chi(2) test. RESULTS: The frequencies for genotypes (chi(2)2=114.69; P<0.001) and alleles (chi(2)1=120.07; P<0.001) between Korean and Croatian individuals differed significantly, due to significantly lower (46.3% and 19.5%, P<0.001) frequency of "Met" allele and significantly higher (53.7% and 80.5%, P<0.001) frequency of "Val" allele in Croatian than in Korean participants. CONCLUSION: The study found significant ethnic differences in BDNF val66met polymorphism. The most frequent genotype among Korean participants was "Met/Val" and they had similar distribution of "Met" and "Val" alleles. In contrast, the most frequent genotype among Caucasian participants was "Val/Val" and they had different distribution of "Met" and "Val" alleles. These ethnic differences require matching participants for ethnicity in pharmacogenetic studies and in the studies investigating genetic variations in neuropsychiatric disorders.