Prenatally Diagnosed 7q11.23 Copy Number Variations: A Retrospective Case Series

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).

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.

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.

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.