RÉSUMÉ
<p><b>OBJECTIVE</b>To study the frequency distribution of flavin-containing monooxygenase 3 (FMO3) mutant alleles in 28 populations originating from 24 ethnic minorities in Yunnan of China.</p><p><b>METHODS</b>FMO3 genotypes were analyzed by polymerase chain reaction-restriction fragment length polymorphism.</p><p><b>RESULTS</b>The average frequencies of FMO3/Stop(148), FMO3/Lys(158) and FMO3/Gly(308) were 0.395(0.174-0.803), 0.208 (0.056-0.414), 0.046(0-0.217), respectively. The frequencies of FMO3/Gly(308) in Blang, Huayaodai, Shuidai, Zhuang, De'ang, Jingpo, Nu and Hui populations were null.</p><p><b>CONCLUSION</b>It was found that the frequencies of FMO3 mutant alleles varied not only in different ethnic groups, but also in different populations that stemmed from the same ethnic group.</p>