[Prenatal diagnosis for 30 women carrying a FMR1 mutation].

Objective: To determine the CGG repeat number and methylation status of FMR1 gene for fetuses whose mothers have carried a FMR1 mutation.

Methods: For 30 pregnant women, the fetal CGG repeat number was determined with a GC-rich PCR system by using chorionic villus, amniotic fluid or umbilical blood samples. The methylation status of the FMR1 gene was confirmed with Southern blotting.

Results: In total 30 prenatal diagnoses were performed for 29 carriers of FMR1 gene mutations and 1 with FMR1 gene deletion mosaicism. Three fetuses were found to carry premutations, 9 were with full mutations and 1 with mosaicism of premutation and full mutations. Eighteen fetuses were normal.

Conclusion: Considering the genetic complexity of Fragile X syndrome (FXS), single method may not suffice accurate determination of their genetic status. The pitfalls and technical limitations of protocols requires adoption of personalized strategy for its prenatal diagnosis.