Prenatal diagnosis of two Turner syndrome fetuses with 46,X,i(X)(q10)

Objective To summarize the prenatal diagnosis and genetic counseling of Turner syndrome fetuses with 46,X,i(X)(q10). Methods Two gravidas admitted to the Obstetrics and Gynecology Hospital of Dalian were enrolled in this study. One gravida, who was admitted in October 2016, was classified as high risk of Down syndrome based on prenatal serologic screening and systematic ultrasonography, which found remarkably shorter humeri and femora than fetus of the same gestations. The other was suggested to be monosomy X after non-invasive prenatal testing and admitted in November 2017. Fluorescence in situ hybridization (FISH) and karyotyping were performed for prenatal diagnosis. Peripheral blood karyotyping was also offered to the two women and their partners. Results FISH test for amniotic fluid did not find numerical abnormality in 13, 18, 21, and sex chromosomes in these two fetuses. Karyotype analysis showed that the two fetuses were both 46, X, i(X) (q10), while their parents were normal. Both cases were terminated after genetic counseling. Conclusions Prenatal serological screening, systematic ultrasonography and non-invasive prenatal testing may help to identify Turner syndrome fetus of 46, X, i(X) (q10). Timely and accurate prenatal diagnosis may prevent the affected fetus from being born. Key words: Turner syndrome; Prenatal diagnosis; Genetic counseling; Isochromosomes