Prenatal diagnosis, ultrasound findings, and pregnancy outcome of 17q12 deletion and duplication syndromes: a retrospective case series.

OBJECTIVE

Analyze the ultrasound findings, single-nucleotide polymorphism array (SNP-array) results, and pregnancy outcomes of fetuses with 17q12 deletions and duplications in the second and third trimesters. Explore the prenatal ultrasound characteristics and pregnancy outcomes of these fetuses.

METHODS

Retrospective data were collected for 16 fetuses diagnosed with 17q12 deletion and seven fetuses with 17q12 duplication through SNP-array during prenatal diagnosis at a single Chinese tertiary medical center from January 2017 to December 2023. Maternal demographics, ultrasound findings of the fetuses, SNP-array results, pregnancy outcomes, and follow-up information were reviewed and analyzed. Peripheral blood from the parents was extracted to determine whether the CNVs in the fetuses were inherited or de novo.

RESULTS

The copy-number variation (CNV) sizes ranged from 1.39 to 1.94 Mb in cases of 17q12 deletion and from 1.42 to 1.91 Mb in cases of 17q12 duplication. These CNVs included 15 OMIM genes, such as HNF1B, LHX1, and ACACA. In fetuses with a 17q12 deletion, the primary manifestation was renal abnormalities (93.8%, 15/16). Of these, 13 cases (81.3%, 13/16) exhibited bilateral or unilateral hyperechogenic kidneys, and 12 cases (75%, 12/16) had multicystic hyperechogenic kidneys. Two cases (12.5%, 2/16) showed multiple organ structural abnormalities. In fetuses with a 17q12 duplication, four cases (57.1%, 4/7) revealed cardiovascular system abnormalities, including tetralogy of fallot, pulmonary artery stenosis, ventricular septal defect, and tricuspid regurgitation. Two cases (28.6%, 2/7) presented with upper gastrointestinal obstruction. Additionally, one case was particularly unique, characterized by multiple structural malformations, such as ventricular septal defect, microcephaly, cleft lip, and palate. Nine cases opted for pregnancy termination, and 14 chose to continue the pregnancy. Two cases underwent surgical treatment after birth for upper gastrointestinal obstruction, and the prognosis was good. Among the 10 cases of 17q12 deletion, six cases showed consistent prenatal ultrasound findings and postnatal clinical features. Four cases were found to have discrepancies with prenatal ultrasound findings; while the renal ultrasound phenotype appeared normal during the last follow-up, two of these cases were subsequently diagnosed with neuropsychiatric phenotypes.

CONCLUSION

Our study expanded the clinical phenotype spectrum of fetuses with 17q12 deletion and duplication, and conducted a preliminary evaluation of prenatal ultrasound findings and postnatal clinical phenotypes in follow-up cases. We further demonstrated a high correlation between fetuses with 17q12 deletion and hyperechogenic, multicystic kidneys. The primary manifestations in fetuses with 17q12 duplication are likely cardiovascular system malformations, which also exhibit a broad spectrum of phenotypic features.