Prenatal diagnosis and genetic counseling of a uniparental isodisomy of chromosome 8 with no phenotypic abnormalities

Chunjiao Yu; Ying Tian; Liang Qi; Bo Wang

doi:10.1186/s13039-022-00594-1

Prenatal diagnosis and genetic counseling of a uniparental isodisomy of chromosome 8 with no phenotypic abnormalities

Mol Cytogenet. 2022 Apr 26;15(1):18. doi: 10.1186/s13039-022-00594-1.

Authors

Chunjiao Yu^#¹, Ying Tian^#², Liang Qi^#³, Bo Wang⁴

Affiliations

¹ Department of Prenatal Diagnosis Center, Maternal, Child Health Hospital of Hubei Province, Wuhan, Hubei, People's Republic of China.
² Department of Obstetrics, Maternal, Child Health Hospital of Hubei Province, Wuhan, Hubei, People's Republic of China.
³ Department of Ophthalmology, Maternal, Child Health Hospital of Hubei Province, Wuhan, Hubei, China.
⁴ Department of Clinical Laboratory, Maternal, Child Health Hospital of Hubei Province, Wuhan, Hubei, People's Republic of China. wangbo1005@163.com.

^# Contributed equally.

Abstract

Background: Uniparental disomy (UPD) refers to an epigenomic abnormality in which both copies of, or a part of, a homologous pair of chromosomes are inherited from one parent. UPD arises via a number of mechanisms, including monosomic and trisomic rescue (in embryonic development), incomplete segregation of chromosomes, and mitotic recombination.

Case presentation: A 34-year-old, gravida 2, para 0 woman underwent amniocentesis at 18 weeks of gestation because the noninvasive prenatal testing (NIPT) showed the highly possibility of trisomy chromosome 8. GTG-banding karyotype analysis was performed on cultured amniocytes. Chromosomal microarray analysis (CMA), fluorescence in situ hybridization(FISH), whole-exome sequencing(WES) on uncultured amniocytes were performed.

Results: CMA detected a 29.4 Mb uniparental isodisomy of chromosome 8, arr 8p23.3p12(168484_29427840) × 2 hmz [GRCh37(hg19)]. FISH, WES and ultrasound examination showed no abnormal. At the 36-month checkup, the baby was developing normally.

Conclusion: Combination of NIPT,prenatal ultrasound, karyotype analysis, CMA, FISH, WES and genetic counseling will prove a more accurate risk assessment for the prenatal diagnosis of UPD.

Keywords: Chromosomal microarray analysis; Fluorescence in situ hybridization; Noninvasive prenatal testing; Uniparental disomy; Whole-exome sequencing.