Prenatal diagnosis of two fetuses with renal structural anomalies caused by 17q12 deletion syndrome

Objective To analyze the prenatal clinical characteristics and genetic diagnosis of two fetuses with chromosome 17q12 deletion syndrome mainly manifested by renal structural abnormalities. Methods Clinical data of two pregnant women admitted to Peking University First Hospital in 2017 due to ultrasound indication of fetal kidney structure abnormality in the second trimester were collected. Results of fetal chromosome karyotype analysis and array-based comparative genomic hybridization (aCGH), and aCGH detection of peripheral blood in the two couples were reviewed. Results (1) In both pregnancies of case 1 and case 2, no abnormal chromosome karyotype was found. In case 2, the fetal fluorescence in situ hybridization (FISH) results showed no abnormality. (2) During the first pregnancy of case 1, there was a 1.351 Mb of single-copy deletion in chromosome 17q12 (34 817 422-36 168 104) and a 1.187 Mb of single-copy duplication in chromosome 3p26.3 (838 934-2 026 269) extracted from umbilical cord blood. Moreover, a 1.299 Mb of single copy duplication in chromosome 3p26.3 (726 645-2 026 269) extracted from maternal peripheral blood was detected. (3) DNA analysis of the umbilical cord blood of case 2 showed a 1.351 Mb of single copy deletion in 17q12. No abnormal copy number variants (CNVs) were detected in the peripheral DNA of the couple. Conclusions Invasive prenatal detection of CNVs in cases with abnormal fetal kidney ultrasound findings might help to confirm the diagnosis and guide genetic counseling. Key words: Chromosome deletion; Chromosomes, Human, Pair 17; Ultrasonography, prenatal; DNA copy number variations; Kidney; Congenital abnormalities