Prenatal Diagnosis and Clinical Phenotypic Heterogeneity of 22q11.2 Microdeletion Syndrome Based on a Single Center Retrospective Study.

Objective: To retrospectively investigate the incidence of prenatal diagnosis of 22q11.2 microdeletion syndrome (22q11.2DS) in a single center and summarize its clinical manifestations to expand the phenotypic database.

Methods: Pregnant women who underwent prenatal diagnosis at The Women and Children's Hospital, School of Medicine, Xiamen University, from January 2018 to February 2024 were retrospectively analyzed. Prenatal diagnosis was performed using routine G-banding karyotype analysis and chromosomal microarray analysis (CMA) or copy number variation sequencing (CNV-seq). Fetuses diagnosed with 22q11.2DS were further analyzed using detailed ultrasound diagnostic records to summarize the clinical manifestations of 22q11.2DS.

Results: A total of 24,319 pregnant women underwent prenatal diagnosis, and 24 cases were diagnosed with 22q11.2DS, with an incidence of 0.99‰ (24/24319), including 16 cases of congenital heart disease, 4 cases of renal pelvis separation, 3 cases of cleft lip and palate, 2 cases of double strephenopodia, 2 cases of nasal bone dysplasia, and 1 case each of unclear thymus, spina bifida with meningomyelocele, abnormal fetal growth retardation, and NT thickening.

Conclusions: Congenital heart disease was the most common phenotype in 22q11.2DS, and other malformations also occurred in a certain proportion. In addition, some rare clinical phenotypes, such as spina bifida with myelomeningocele and nasal bone hypoplasia, were also found in this cohort, which should be taken seriously to improve the detection rate of fetal 22q11.2DS.