Cryptic balanced translocations leading to adverse pregnancy outcomes: genetic analysis of five pedigrees
10.3760/cma.j.cn113903-20240222-00141
- VernacularTitle:5个隐匿性平衡易位致不良妊娠结局家系的遗传学分析
- Author:
Caiqin GUO
1
;
Jianping XIAO
;
Lan YANG
;
Junfeng WANG
;
Yu CUI
;
Zeling SANG
;
Jun LIU
Author Information
1. 无锡市妇幼保健院（江南大学附属妇产医院）医学遗传与产前诊断科，无锡 214002
- Keywords:
Adverse pregnancy;
Cryptic balanced translocation;
Chromosome microarray analysis;
Fluorescence in situ hybridization;
Prenatal diagnosis
- From:
Chinese Journal of Perinatal Medicine
2024;27(11):937-942
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To identify the genetic causes of adverse pregnancy outcomes in five families and provide a basis for rational guidance on genetic and reproductive counseling.Methods:A retrospective analysis was conducted on five families with a history of adverse pregnancy outcomes, where one partner was found to have a cryptic balanced translocation. These cases were identified among pregnant women who underwent invasive prenatal diagnosis at the Department of Medical Genetics and Prenatal Diagnosis, Wuxi Maternity and Child Health Care Hospital, from January 2016 to June 2023. Conventional G-banding karyotyping and chromosomal microarray analysis (CMA) were performed on affected children/fetus samples. Chromosome G-banding and fluorescence in situ hybridization (FISH) were used for parental tracing. Genetic counseling was provided for all cases, and the pregnancy outcomes were followed up. Descriptive analysis was applied in this study. Results:Case 1 involved an eldest son with unexplained intellectual disability, and the CMA results showed an 8.6 Mb deletion in the 4p16.3p16.1 region and a 1.0 Mb duplication in the 7q36.3 region. Unbalanced translocations were detected in the current pregnancies of the other four cases, which were a 6.1 Mb duplication in the 14q32.2q32.33 region with a 1.6 Mb deletion in the 21q22.3 region (Case 2), a 10.8 Mb duplication in the 6q25.3q27 region with a 1.2 Mb deletion in the 15q26.3 region (Case 3), a 1.0 Mb duplication in the 5p15.33 region with a 2.9 Mb deletion in the 6q27 region (Case 4), and a 3.2 Mb deletion in the 1q44 region with a 4.8 Mb duplication in the 19p13.3 region (Case 5). FISH confirmed that either the husband or the wife in each of the five families was a carrier of a cryptic balanced translocation. Further CMA testing on amniotic fluid samples from previous terminated pregnancies of Cases 3 and 4 also indicated unbalanced translocations. Both the current pregnancy of Case 1 and the subsequent pregnancy of Case 2 gave birth to healthy babies after non-abnormal prenatal diagnosis and genetic counseling. Cases 3 to 5 are currently preparing for pregnancy.Conclusion:Advances and combined application of genetic technologies will be conducive to improving the diagnosis of cryptic balanced translocations in some families with adverse pregnancy outcomes, providing a sound basis for genetic counseling in future pregnancy.
