Abstract
BACKGROUND: Williams-Beuren syndrome (WBS; OMIM #194050), caused by 7q11.23 deletions, is well-characterized postnatally, but prenatal manifestations remain poorly defined. This study aims to delineate the prenatal phenotypes, inheritance patterns, and outcomes of 7q11.23 copy number variations (CNVs). METHODS: A retrospective study of 20 prenatal cases with 7q11.23 CNVs diagnosed by SNP array or CNV sequencing (CNV-seq) was conducted. Clinical data, including ultrasound findings, genetic results, and pregnancy outcomes, were analyzed. RESULTS: Classic 7q11.23 deletions (1.42 Mb median size) were associated with ultrasound anomalies in 100% of cases (11/11), predominantly cardiovascular defects (36.4%, 4/11) and growth restriction (18.2%, 2/11). While 7q11.23 duplications (1.42-3.03 Mb) were associated with anomalies in 50% of cases (3/6), including cleft palate and ventriculomegaly. Inheritance pattern analysis revealed 50% of deletions (6/12) and 42.9% of duplications (3/7) were inherited, either from phenotypically normal or abnormal parents. Termination of pregnancy (TOP) occurred in 76.5% (13/17) of ongoing pregnancies, primarily for de novo CNVs. Four live births involved inherited CNVs. CONCLUSION: 7q11.23 CNVs exhibit significant prenatal phenotypic variability and inheritance heterogeneity. Advanced genomic testing and inheritance pattern analysis are critical for accurate diagnosis and counseling.