Results of carrier screening and prenatal diagnosis for FMR1 gene in 819 cases / 中华医学遗传学杂志

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.

Research on values of ultrasound measuring of placenta thickness at the early pregnancy for evaluating risks of alpha-thalassemia / 中华超声影像学杂志

Objective To investigate the values of ultrasound measuring of the placenta thickness on evaluation of risks for alpha-thalassemia at the early pregnancy.Methods Two-dimensional ultrasound was performed to measure the thickness of placenta on 208 cases of fetuses with alpha-thalassemia and 52 cases of normal fetuses in control group.The placenta thickness was expressed as multiples of the median(MOM).Results At the early pregnancy,the group of fetuses with alpha-thalassemia had significantly higher placenta thickness compared to the fetuses without alpha-thalassemia(P＜0.001).However,there were no statistical significant difference in the placenta thickness between the other groups(P=0.100).Placenta thickness 1.18 MOM was the best critical point to predict alpha-thalassemia.The sensitivity and specificity of placenta thickness >1.18 MOM in prediction of alpha-thalassemia was 82.9%,84.7% respectively.Conclusions For those with high risks of alpha-thalassemia placenta thickness measuring is a safe,effective parameter for assessment because it could reduce unnecessary invasive procedures and improve the detecting rate of severe alpha-thalassemia.