Fragile X syndrome prenatal diagnosis: parental attitudes and reproductive responses.

Fragile X syndrome (FXS) is the most common inherited form of mental retardation. It is caused by a CGG repeat expansion, which results in hypermethylation and silencing of the FMR1 gene. The results from 213 FXS prenatal diagnoses performed in the study centre were reviewed. Family history of FXS or undiagnosed mental retardation (MR) were the reasons for referral and 64% of mothers were not aware of their status so prenatal and mother tests were performed at the same time. Among those women referred for family history of unknown MR, 17.6% were found to be FXS carriers. The attitudes and perceptions of the syndrome of 52 FXS carriers were also evaluated. Most of them had been diagnosed as carriers when the child was already born and the most common feeling was sadness, followed by impotence and guilt. The majority of them had received genetic counselling and they considered it useful. Regarding reproductive options, prenatal diagnosis was chosen by 40.5% of women. Prenatal diagnosis for FXS is a good reproductive option and it should be carried out whenever family history of MR is present. A high percentage of FXS carriers are detected following this approach.