Clinical Research
Detection rate and clinical significance of regions of homozygosity in prenatal genetic diagnosis
Zhu Lifen, Zhang Huimin, Mai Lihua, Sun Xiaofang, Liu Weiqiang
Published 2022-04-25
Cite as Chin J Obstet Gynecol, 2022, 57(4): 271-277. DOI: 10.3760/cma.j.cn112141-20210820-00455
Abstract
ObjectiveTo detect the incidence and analyze the clinical significance of regions of homozygosity (ROH) through the single nucleotide polymorphism array (SNP array).
MethodsThe SNP array detection results of 5 116 pregnant women in the Third Affiliated Hospital of Guangzhou Medical University from January 2016 to December 2020 were retrospectively analyzed. The pregnant women with ROH (5 Mb as the threshold) were followed up to analyze the relationship between ROH and abnormal fetal phenotype. Whole exon sequencing was performed in 4 cases of consanguineous marriage to detect potential recessive causative genes in the ROH region.
Results(1) A total of 39 cases of ROH were detected, with a positive rate of 0.76% (39/5 116). Among them, 25 cases (64%, 25/39) were detected only on single chromosome, and chromosome 11 had the highest detection rate, suggesting the risk of uniparental disomy; fourteen cases (36%,14/39) were detected on multiple chromosomes, most commonly on chromosomes 11, 1, 3, 4 and 8. (2) The number of cases and detection rate of ROH detected by different prenatal diagnosis indicators were as follows: 12 cases (1.78%, 12/676) in pregnant women with abnormal non-invasive prenatal testing result, 12 cases (0.37%, 12/3 284) in pregnant women with ultrasound abnormality, 4 cases (4/4) in pregnant women with consanguineous marriage, 3 cases (0.92%, 3/326) in pregnant women with previous adverse pregnancy, 2 cases (1.15%, 2/174) in pregnant women with high risk of serology in screening, 2 cases (4.00%, 2/50) in pregnant women with abnormal fetal chromosomal karyotype, 2 cases (0.79%, 2/253) in pregnant women with advanced maternal age, 1 case (0.56%, 1/178) in pregnant women with related parental genetic factors and 1 case (0.58%, 1/171) in pregnant women with the other factors. (3) The follow-up results of 39 cases of prenatal ROH showed that there were 16 cases of term birth, 15 cases of termination of pregnancy, 2 cases of preterm births, 1 case of fetal death and 5 cases lost to follow-up.
ConclusionsChromosomal ROH phenomenon is not rare. By analyzing the detection rate of ROH in prenatal diagnosis, combined with the results of fetal phenotype and postpartum follow-up, the clinical characteristics of ROH are discussed, so as to better understand the relationship between ROH and its phenotype.
Key words:
Uniparental disomy; Polymorphism, single nucleotide; Microarray analysis; Genetic counseling; Prenatal diagnosis; Regions of homozygosity
Contributor Information
Zhu Lifen
Department of Obstetrics and Gynecology, Guangdong Provincal Key Laboratory of Major Obstetric Diseases, the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China
Zhang Huimin
Department of Obstetrics and Gynecology, Guangdong Provincal Key Laboratory of Major Obstetric Diseases, the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China
Mai Lihua
Department of Obstetrics and Gynecology, Guangdong Provincal Key Laboratory of Major Obstetric Diseases, the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China
Sun Xiaofang
Department of Obstetrics and Gynecology, Guangdong Provincal Key Laboratory of Major Obstetric Diseases, the Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, China
Liu Weiqiang
Central Laboratory, Shenzhen Longgang District Maternity and Child Healthcare Hospital, Shenzhen 518172, China
