Analysis of the polymorphisms of genes coding biotransformation enzymes in recurrent miscarriage in the Japanese population

Abstract Aim: To investigate the relationship between the genotype of enzymes for detoxification and recurrent miscarriage. Methods: The frequency of each genotype of enzymes for detoxification, such as cytochrome P450‐1A1 (CYP1A1), glutathione‐S‐transferase‐pi (GST‐pi), GST‐mu and GST‐theta, was analyzed in patients with unexplained recurrent miscarriage (number of miscarriages ≥3) by polymerase‐chain reaction‐restriction fragment length polymorphism. A total of 103 patients were enrolled in the study, and 101 normal fertile women, who had never suffered a miscarriage, were also enrolled. The frequency of each genotype of the enzymes was compared between the patient population and the control group. The χ 2 ‐test and Fisher's exact test were used for statistical evaluation. Results: No significant difference was observed concerning the distribution of polymorphic variants among CYP1A1, GST‐pi, GST‐mu and GST‐theta. On the other hand, the frequency of individuals with the GST‐mu deletion was significantly higher in cases of recurrent miscarriage compared with the control population among coffee drinkers (61% vs 41%, P = 0.025). Conclusion: There is a possibility that lower GST‐mu enzyme activity may represent a risk factor for recurrent miscarriage, especially in the patient population of coffee consumers, as a result of impaired placental detoxification.