Abstract:

13-trisomy syndrome is a serious and rare chromosomal disease caused by complete or partial trisomy of chromosome 13. The prevalence is about 1.68/10 000, of which 13-trisomy syndrome caused by partial trisomy 13q accounts for 1%. The maternal partial trisomy 13q and partial monosomy 21q are even less. We reported a pregnant woman undergoing further prenatal diagnosis and genetic analysis in the Second Hospital Affiliated to Army Medical University, due to the abnormal fetal development indicated by ultrasound at 23⁺¹ weeks of gestation. Ultrasound showed the subvalvular aortic ventricular septal defect, double superior vena cava and abnormal ossification of vertebral body. The karyotype of amniotic fluid was 46,X?,+der(13)t(13;21)(q32;q21)dmat,-21. Copy number variation sequencing (CNV-seq) showed seq[hg19]dup(13)(q11q32.1)chr13:g.19440000_ 97680000dup and seq[hg19]del(21)(q11.2q21.1)chr21:g.15060000_22020000 del. The maternal karyotype was 46,XX,t(13;21)(q32;q21). Fetal chromosomal abnormalities were caused by the mother′s chromosomal balance translocation, which was the main reason of fetal heart development abnormalities. The comprehensive application of chromosome karyotype analysis and CNV-seq can identify the origin and nature of chromosome abnormalities, and provide a basis for genetic counseling and reproductive guidance.

Key words: Trisomy, Monosomy, Congenital abnormalities, Karyotyping, DNA copy number variations, Prenatal diagnosis