Wu Yong, Liao Chuanning, Xie Yamei, Wang Lingxi
Prenatal Diagnosis Center, Chengdu Women's and Children's Central Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.
Mol Syndromol. 2024 Feb;15(1):71-76. doi: 10.1159/000531769. Epub 2023 Sep 18.
Chromosomal aberrations due to complex chromosomal rearrangements (CCRs) can cause abnormal phenotypes if accompanied by microdeletions or microduplications near the breakpoint, or gene breaks.
We report a prenatal diagnostic case of 2q14.3-q22.1 deletion with ultrasound suggestive of absent nasal bone accompanied by CCRs involving 6 chromosomes. Cytogenetic analysis revealed a karyotype of 46,XY,der(1)t(1;2)(p13.3;p11.2),der(2)t(1;2)inv(2)(q12q14.2)del(2)(q14.3q22.1),t(12;16)(q21.2;q12.1),t(13;21)(q32;q22.1). Chromosomal microarray analysis identified a 14.90 Mb deletion on 2q14.3q22.1. The copy number variant was de novo, as determined by karyotype analysis of the parents' peripheral blood G-banding.
The region contains haploinsufficient genes that can cause different phenotypes, mainly associated with neurodevelopmental and autism spectrum disorders. However, the genotype-phenotype correlation is limited in prenatal evaluation. Therefore, the combined use of multiple diagnostic techniques has an important role in the assessment of CCRs and genetic counseling.
由于复杂染色体重排(CCR)导致的染色体畸变,如果在断点附近伴有微缺失或微重复,或基因断裂,可能会导致异常表型。
我们报告一例产前诊断的2q14.3 - q22.1缺失病例,超声提示鼻骨缺失,并伴有涉及6条染色体的CCR。细胞遗传学分析显示核型为46,XY,der(1)t(1;2)(p13.3;p11.2),der(2)t(1;2)inv(2)(q12q14.2)del(2)(q14.3q22.1),t(12;16)(q21.2;q12.1),t(13;21)(q32;q22.1)。染色体微阵列分析确定2q14.3q22.1存在14.90 Mb的缺失。通过对父母外周血G显带进行核型分析确定该拷贝数变异为新发突变。
该区域包含单倍剂量不足的基因,可导致不同表型,主要与神经发育和自闭症谱系障碍相关。然而,在产前评估中,基因型与表型的相关性有限。因此,多种诊断技术的联合应用在CCR评估和遗传咨询中具有重要作用。