Tryptophan hydroxylase gene polymorphism (A218C) and idiopathic recurrent miscarriage

OBJECTIVE: To investigate the frequency of a polymorphism in intron 7 of th e tryptophan hydroxylase gene among women with idiopathic recurrent miscarr iage and healthy controls. METHODS: In a case control study, we studied 125 women with a history of th ree or more consecutive pregnancy losses before 20 weeks' gestation and 137 healthy controls with at least two live births and no history of pregnancy loss. Peripheral venous puncture, DNA extraction, and polymerase chain rea ction followed by restriction fragment length polymorphism analysis were us ed to genotype women for the presence of the A218C polymorphism in intron 7 of the tryptophan hydroxylase gene. RESULTS: Allele frequencies among women with idiopathic recurrent miscarria ge and controls were 32.4% and 38.7%, respectively, for allele A (wild type ) and 67.6% and 61.3%, respectively, for allele C (mutant). No association between the presence of allele C and idiopathic recurrent miscarriage was f ound (P =.3; odds ratio 1.31; 95% confidence interval 0.93, 1.87). Genotype frequencies also were not significantly different between the study group (C/C: 44.8%; A/C: 45.6%; A/A: 9.6%) and the control group (C/C: 37.2%; A/C: 48.2%; A/A: 14.6%; P =.2). Between women with primary and women with secon dary idiopathic recurrent miscarriage, no statistically significant differe nces with respect to allele frequencies were observed (63% vs 62% for allel e C and 31% vs 38% for allele A; P =.3). CONCLUSION: The A218C polymorphism in intron 7 of the tryptophan hydroxylas e gene is not associated with idiopathic recurrent miscarriage. (C) 2001 by the American College of Obstetricians and Gynecologists.)