Mosaic male fetus of Turner syndrome with partial chromosome Y: A case report.

Turner syndrome, characterized by the presence of a monosomy X cell line, is a common chromosomal disorder. Patients with Turner syndrome are usually phenotypically female, and male cases are rarely reported. Here, we report a fetus with a mosaic karyotype: mos 45,X/46,X,del(Y)(q11.21). The fetus was initially misdiagnosed as female with Turner syndrome by both noninvasive prenatal testing and cytogenetic analysis of amniotic fluid and was subsequently found to have male anatomy by antenatal ultrasonography at 24 weeks gestational age. Through single nucleotide polymorphism-array and fluorescence in situ hybridization testing, we found that there was a truncated Y chromosome with sex-determining region Y (SRY) present in some cells of the fetus, which caused the male features in the fetus.