RESUMO
Cytochrome P450 family genes (CYPs) have common polymorphisms, which are evaluated for pesticide-inducedoxidative stress susceptibility. Variant alleles in CYP enzymes may uncover susceptibility biomarkers of environmentaltoxicity. This study aims to investigate the relationship between CYP2D6 (G1934A) gene polymorphisms and chronicpesticide exposures, and to evaluate the association between CYP2D6 (G1934A) gene polymorphism on biochemicaland hematological parameters. A cross-sectional study was carried out at a health promoting hospital, Suphan Buri,Thailand. Rice farmers and a control group (n = 50 for each) were recruited and their personal data were collected. Theirblood samples were obtained by venepuncture and drawn into plain and Ethylenediaminetetraacetic acid (EDTA) tubes.Serum cholinesterase (SChE), liver function test, kidney function test, and complete blood count were assessed usingautomatic analyzers; and CYP2D6 (G1934A) genotyping was carried out by polymerase chain reaction-restrictionfragment length polymorphism (PCR-RFLP). SChE in rice farmers was significantly lower (p = 0.033), which maybe related to the use of chlorpyrifos. The genotypes were significantly different between rice farmers and the controlgroup (p = 0.0001), and the GA variant in rice farmers was more frequent. The CYP2D6 (G1934A) (rs 3892097))gene and SChE level were negatively correlated (r = −0.258, p = 0.009). However, other biochemical parameters werenot different. Blood indices, including mean corpuscular hemoglobin (MCH), mean corpuscular volume (MCV), andmean corpuscular hemoglobin concentration (MCHC), values of rice farmers were significantly lower than the controlgroup; and MCH, MCV, and MCHC values of the GA variant were also significantly lower than the wild type. The GAgenotype was associated with hematological toxicity of organophosphate metabolite in chronic exposures.