Genetic Analysis of Prenatal Renal Abnormalities in 17q12 Microdeletion Syndrome.

Objective: To analyze fetal renal abnormality genetic features and the prenatal characteristics of the 17q12 microdeletion syndrome. Methods: This prospective cohort study examined prenatal ultrasound findings of renal abnormalities in pregnant women who underwent single nucleotide polymorphism (SNP) array or copy number variation sequencing (CNV-seq) testing on amniotic fluid or fetal tissue at Tianjin Central Obstetrics and Gynecology Hospital between January 2016 and August 2022. The study cohort comprised women with advanced maternal age, fetal ultrasound anomalies, high-risk non-invasive prenatal testing results, or suspected 17q12 microdeletion syndrome. Comprehensive clinical data, including maternal age, detailed ultrasound findings, and pregnancy outcomes, were systematically collected. SNP-array analysis was conducted using an Affymetrix CytoScan 750 K Array Chip to identify CNVs and loss of heterozygosity, while CNV-seq was performed on the Illumina HiSeq 2000 platform. Detected variants were classified according to the American College of Medical Genetics and Genomics guidelines. Statistical analyses were performed using SPSS version 27.0. Results: Abnormal renal development was identified in 141 patients, among whom 26 exhibited hyperechogenic kidneys (HCK). Of these, 12 cases were associated with 17q12 microdeletion syndrome, while the remaining 14 were linked to other chromosomal abnormalities. When excluding patients with HCK, those diagnosed with polycystic kidney disease demonstrated a higher prevalence of chromosomal abnormalities compared to those with multicystic dysplastic kidney and renal dysplasia. Although isolated conditions such as horseshoe kidney, hydronephrosis, ectopic kidney, and unilateral kidney typically presented with normal chromosomal findings, the incidence of chromosomal abnormalities increased when these conditions coexisted with other anomalies. A detailed analysis of the correlation between 17q12 microdeletion syndrome and HCK revealed that 12 out of the 14 patients diagnosed with 17q12 microdeletion syndrome exhibited HCK. Genetic testing confirmed the syndrome in seven patients, with five cases attributed to novel mutations and two cases resulting from inherited mutations. Conclusion: Fetal HCK was closely associated with the 17q12 microdeletion syndrome, and polycystic kidney disease showed a higher rate of chromosomal abnormalities. Chromosome test results were mostly normal in patients with other renal abnormalities, such as kidney dysplasia, horseshoe kidneys, hydronephrosis, kidney deficiency, and ectopic kidneys. Prenatal diagnosis is recommended, especially in cases of non-isolated fetal renal abnormalities. This study provides strong evidence supporting a link between fetal renal abnormalities and genetic syndromes.