The article presents a study that determines the distribution of fragile X mental retardation 1 (FMR1) alleles and the prevalence of permutation (PM) and full mutation (FM) of the gene in Korean women. It describes the method of the study that uses polymerase chain reaction and Southern blot on 5829 of reproductive age. It notes the result of the study which indicates the carrier frequency in Korean women of reproductive age, which is lower than the Caucasians.