Prenatal diagnosis and genetic counseling of an inherited unbalanced chromosome abnormalities in a Chinese family

Ying Zhang; Juan Chen; Zonghui Feng; Wencheng Li

doi:10.1186/s13039-022-00614-0

Prenatal diagnosis and genetic counseling of an inherited unbalanced chromosome abnormalities in a Chinese family

Mol Cytogenet. 2022 Aug 15;15(1):34. doi: 10.1186/s13039-022-00614-0.

Authors

Ying Zhang^#^{1

2

3

4}, Juan Chen^#^{1

2

3

4}, Zonghui Feng^#⁵, Wencheng Li⁶

Affiliations

¹ Reproductive Medicine Center, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, People's Republic of China.
² Prenatal Diagnosis Center, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, People's Republic of China.
³ Hubei Clinical Research Center for Reproductive Medicine, Shiyan, Hubei, People's Republic of China.
⁴ Biomedical Engineering College, Hubei University of Medicine, Shiyan, Hubei, People's Republic of China.
⁵ Prenatal Diagnosis Center, Maternity and child Care Hospital of Huaihua, Huaihua, Hunan, People's Republic of China.
⁶ Prenatal Diagnosis Center, Maternity and child Care Hospital of Huaihua, Huaihua, Hunan, People's Republic of China. wuyijunhg@126.com.

^# Contributed equally.

Abstract

Background: Unbalanced chromosome abnormalities (UBCA) are either gains or losses or large genomic regions, but the affected person is not or only minimally clinically affected. Copy number variants (CNVs) are an important source of normal and pathogenic genome variations. CNVs and UBCA identified in prenatal cases need careful considerations and correct interpretation if those are harmless or harmful variants from the norm.

Case presentation: A 25-year-old, gravida 1, para 0, woman underwent amniocentesis at 18 weeks of gestation because the noninvasive prenatal testing (NIPT) results revealed a 6.8 Mb duplication from 2q11.1 to 2q11.2. Chromosomal microarray analysis (CMA) was performed on uncultured amniocytes. GTG-banding karyotype analysis on cultured amniocytes was performed.

Results: Chromosomal GTG-banding of the cultured amniocytes revealed a karyotype of 46,XX. CMA detected a 6.8-Mb chromosomal duplication in the region of 2q11.1q11.2 (arr[GRCh37] 2q11.1q11.2(95,327,873_102,088,148)x3).

Conclusion: Chromosomal microdeletions and microduplications are difficult to detect by conventional cytogenetics, combination of prenatal ultrasound, karyotype analysis, NIPT, CMA and genetic counseling is helpful for the prenatal diagnosis of UBCA and chromosomal microdeletions/microduplications.

Keywords: Chromosomal microarray analysis (CMA); Chromosomal microdeletions/microduplications; Noninvasive prenatal testing (NIPT); Prenatal diagnosis; Unbalanced chromosomal abnormalities (UBCA).