Résumé
OBJECTIVE@#To determine the carrier rate of Fragile X mental retardation 1 gene (FMR1) mutants in women with a history of adverse pregnancy or childbirth, and to provide prenatal diagnosis for the carriers.@*METHODS@#Peripheral blood samples were collected from women with a history of adverse pregnancy or childbirth, and the FMR1 gene cytosine-guanine-guanine repeat number (CGG)n was determined by triple-repeat primer polymerase chain reaction (TP-PCR) combined with capillary electrophoresis. Prenatal diagnosis was provided for the carriers during pregnancy.@*RESULTS@#Among 819 samples, 9 gray zone repeats carriers and 10 premutation carriers were detected, which gave a prevalence of 1 in 91 and 1 in 82, respectively, with a total prevalence of 1 in 43. Prenatal diagnosis was provided during 7 pregnancies for 6 carriers. A female fetus with premutation (n = 30/57) and an affected male fetus with full mutation (n = 336) were detected.@*CONCLUSION@#FMR1 gene testing in women with a history of adverse pregnancy or childbirth can facilitate genetic counseling and reproductive guidance for carriers of gray zone repeats and premutations. Prenatal diagnosis for carriers of premutation can facilitate reduction of the birth of children with fragile X syndrome.
Résumé
<p><b>OBJECTIVE</b>To apply single nucleotide polymorphism array (SNP-array) for the diagnosis of Williams-Beuren syndrome (WBS) in a patient.</p><p><b>METHODS</b>Chromosome G-banding and SNP-array were used to analyze a girl featuring mental retardation.</p><p><b>RESULTS</b>The karyotypes of the child and her parents were all normal, but SNP-array showed a 1.9 Mb deletion at 7q11.23 in the patient. The same deletion was not found in her parents.</p><p><b>CONCLUSION</b>The mental retardation and special facies of the girl were probably due to the 7q11.23 microdeletion. SNP-array has an important value for the diagnosis of mental retardation.</p>