Objective:To confirm the potential etiological factors of congenital aortic stenosis(AS)by genetic analysis on prenatal diagnostic results of the fetus with AS.Methods:Amniocentesis for chromosomal G-band karyotyping combinated with single nucleotide polymorphism array(SNP-array)analysis was conducted on the amniotic fluid collected from a 25-week pregnant woman diagnosed as"fetus AS";chromosome karyotyping was also performed on the peripheral blood of the fetal parents.Results:The fetal karyotype analysis showed a chimeric Y-chromosome isobaric double-adherent granules.The SNP-array analysis results revealed a 11.2 Mb duplication in the Yp11.31q11.21 region and a 14.8 Mb deletion in the Yq11.21q11.23 region.Both the parents presented a normal karyotype,suggesting it was a newfound mutation.After extensive genetic counseling,the pregnant woman and her family chose to terminate the pregnancy locally.Conclusion:The chromosomal karyotype of the chimeric Y-chromosome isobaric double-adherent granules may be a contributing factor to the AS phenotype in the male fetus.The combined use of chromosomal karyotyping and SNP-array analysis on the amniotic cells is instrumental in the early diagnosis of the disease.