Prenatal Diagnosis of 7q11.23 Microdeletion: Two Cases Report and Literature Review

Chromosome microdeletions within 7q11.23 can result in Williams-Beuren syndrome which is a rare autosomal dominant disorder. Williams-Beuren syndrome is usually associated with developmental delay, cardiovascular anomalies, mental retardation, and characteristic facial appearance.Two pregnant women underwent amniocentesis for cytogenetic analysis and chromosomal microarray analysis (CMA) because of abnormal ultrasound findings. Case 1 presented subependymal cyst and case 2 presented intrauterine growth restriction, persistent left superior vena cava and pericardial effusion in clinical ultrasound examination.Cytogenetic examination showed that the 2 fetuses presented normal karyotypic results. CMA detected 1.536 Mb (case 1) and 1.409 Mb (case 2) microdeletions in the region of 7q11.23 separately.Both couples opted for the termination of pregnancies based upon genetic counseling.The deleted region in both fetuses overlapped with Williams-Beuren syndrome. To our knowledge, case 1 was the first reported fetus of Williams-Beuren syndrome with subependymal cyst.The genotype-phenotype of Williams-Beuren syndrome is complicated due to the phenotypic diversity. For prenatal cases, clinicians should consider the combination of ultrasonography, traditional cytogenetic, and molecular diagnosis technology when genetic counseling.