[Prenatal diagnosis of two fetuses with de novo 46,X,psu dic(Y)/45,X mosaicism].

Objective To carry out prenatal diagnosis for a fetus with increased nuchal translucency (NT) and another fetus with non-invasive prenatal testing (NIPT) suggested reduced sex chromosomes by cytogenetic and molecular techniques. Methods Chromosomal karyotyping, single nucleotide polymorphism array (SNP-array) and fluorescence in situ hybridization (FISH) were applied for the diagnoses. Peripheral blood samples were also taken from their parents for chromosomal karyotyping and SNP-array analysis. Results Both fetuses showed a 46,X,+mar/45,X karyotype. SNP-array has detected a 22.0 Mb duplication at Yp11.31q11.223 and a 3.9 Mb microdeletion at Yq11.223q11.23 in fetus 1, and a 16.9 Mb duplication at Yp11.31q11.221 and a 8.1 Mb deletion at Yq11.222q11.23 in fetus 2. The results were confirmed by FISH. The parents of both fetuses were normal by chromosomal karyotyping and SNP-array. Conclusion Combined use of various techniques can enable accurate prenatal diagnosis and genetic counseling.