Follow-up and re-evaluation of fetuses with chromosomal microdeletions and microduplications of uncertain significance
10.3760/cma.j.cn113903-20241224-00849
- VernacularTitle:意义未明染色体微缺失微重复胎儿的随访与再评价
- Author:
Can YANG
1
;
Manli ZHANG
;
Xiaoxiao XIE
;
Lingyun HU
;
Qingdong ZHAO
;
Xiaoping WANG
;
Yanqin YOU
;
Shufang JIANG
;
Yanping LU
Author Information
1. 解放军医学院，北京 100853
- Publication Type:Journal Article
- Keywords:
Chromosomal microdeletions and microduplications;
Variants of uncertain significance;
Prenatal diagnosis;
Genetic counseling
- From:
Chinese Journal of Perinatal Medicine
2025;28(3):177-184
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To reassess the pathogenicity of copy number variants (CNVs) involving chromosomal microdeletions and microduplications classified as variants of uncertain significance (VUS).Methods:This retrospective study analyzed 1 882 pregnant women who underwent invasive prenatal diagnosis for chromosomal microarray analysis (CMA) at the First Medical Center, Chinese PLA General Hospital between January 1, 2018, and December 31, 2022. The results were classified according to the American College of Medical Genetics and Genomics guidelines, with 82 fetuses rated as VUS selected for the study. We analyzed invasive prenatal diagnostic indications, followed up on fetal ultrasound findings, parental origin identification results, and pregnancy outcomes, and reclassified VUS CNVs based on the latest evidence. Descriptive statistical analysis was applied to the data.Results:(1) Among the 82 fetuses with VUS CNVs, prenatal diagnostic indications included fetal structural abnormalities detected by ultrasound (21 cases, 25.6%), abnormal non-invasive prenatal testing (NIPT) results (12 cases, 14.6%), high-risk serum screening (seven cases, 8.5%), advanced maternal age (≥35 years at expected delivery, 28 cases, 34.1%), and other indications (14 cases, 17.1%). Sixteen cases (19.5%) exhibited abnormal phenotypes, with seven pregnancies terminated due to severe structural abnormalities detected by prenatal ultrasound. Seventy-five live births were followed up for 25 (13-66) months. (2) Among the 82 cases, five fetuses had two VUS CNVs detected by CMA, while the remaining 77 had only one, totaling 87 VUS CNVs. Of these, 63 (72.4%) were chromosomal microduplications and 24 (27.6%) were chromosomal microdeletions. The size of the CNV segments ranged from 0.85 (0.05-5.61) Mb, with 82 segments less than 2 Mb. Parental origin identification was refused by 44 cases (53.7%), while 38 (46.3%) underwent the test, revealing eight (21.0%) de novo variants and 30 (78.9%) inherited from either parent (12 maternal and 18 paternal). (3) Among the 87 VUS CNVs, the ratings of 11 CNVs (12.6%) changed after re-evaluation. This included one 4p16.2 microdeletion and two 15q11.2 microdeletions being upgraded to pathogenic, one 16p13.11 microduplication being upgraded to likely pathogenic, one Xp22.31 microduplication and two 2q13 microdeletions being downgraded to likely benign, and four Xp22.31 microduplications being downgraded to benign. (4) Among the 16 fetuses with abnormal phenotypes, seven with prenatal abnormalities terminated pregnancies, including six with structural abnormalities and one with severe fetal growth restriction. After re-evaluation, one case was upgraded to pathogenic, while six remained VUS. Nine live births with postnatal abnormal phenotypes showed no change in classification after re-evaluation. Among the 66 cases (80.5%) without abnormal phenotypes, 10 had their classifications changed after re-evaluation. Conclusions:Fetuses with VUS CNVs often exhibit no significant abnormal phenotypes and have a relatively favorable prognosis, however, further floow-up is still needed. Parental origin identification can provide valuable insights for genetic counseling.
