Wang Rong Hua, Wu Ke, Hu Xiao Ling
Department of Laboratory Medicine, Quzhou Maternal and Child Healthcare Hospital, Quzhou, Zhejiang, China.
Laboratory of Prenatal Diagnosis Center, Quzhou Maternal and Child Healthcare Hospital, Quzhou, Zhejiang, China.
Front Genet. 2024 Jul 18;15:1436469. doi: 10.3389/fgene.2024.1436469. eCollection 2024.
A dicentric chromosome is an abnormal chromosome with two centromeres on the same chromosome. It has been reported that dicentric chromosomes are specific biomarkers of radiation exposure, but dicentric chromosomes are rarely identified in newborns with multiple congenital anomalies. At 16 weeks of gestation, a 39-year-old pregnant woman (gravida 2, para 1) was referred to the prenatal diagnosis center for genetic counseling. The fetal ultrasonography indicated multiple anomalies. Subsequently, amniocentesis was performed, and the G-banding karyotype analysis showed a rare type of mosaicism. The C-banding karyotype analysis indicated a pseudo-dicentric chromosome X [psu dic (X; 18) (p11.2; p11.2)]. A single-nucleotide polymorphism array (SNP array) revealed three pathogenic copy number variations (CNVs). After genetic counseling, the parents chose to terminate this pregnancy. This study provides new evidence for a better understanding of the diagnosis of dicentric chromosomes and emphasizes on the importance of genetic counseling.
双着丝粒染色体是一种在同一染色体上有两个着丝粒的异常染色体。据报道，双着丝粒染色体是辐射暴露的特异性生物标志物，但在患有多种先天性异常的新生儿中很少能识别出双着丝粒染色体。在妊娠16周时，一名39岁的孕妇（孕2产1）被转诊至产前诊断中心进行遗传咨询。胎儿超声检查显示有多种异常。随后进行了羊水穿刺，G显带核型分析显示出一种罕见的嵌合类型。C显带核型分析显示一条假双着丝粒X染色体[假双着丝粒(X;18)(p11.2;p11.2)]。单核苷酸多态性阵列（SNP阵列）显示出三个致病性拷贝数变异（CNV）。经过遗传咨询后，父母选择终止此次妊娠。本研究为更好地理解双着丝粒染色体诊断提供了新证据，并强调了遗传咨询的重要性。
