Prenatal diagnosis of 17q12 deletion syndrome: a retrospective case series

The 17q12 deletion syndrome is a chromosomal anomaly resulting from the interstitial microdeletion of the long arm of chromosome 17. The aim of this study was to present the experience on prenatal diagnosis of 17q12 deletion to further define the prenatal phenotypes of this syndrome. Eleven pregnancies with foetal 17q12 deletion detected by chromosomal microarray (CMA) were retrospectively included at a single Chinese tertiary medical centre. Clinical data were reviewed for these cases, including the maternal demographics, foetal ultrasound findings, CMA results and pregnancy outcomes. The deletion sizes of 17q12 ranged from 1.42 to 1.94 Mb. The deletion had arisen de novo in 10 cases and inherited from one of the parents in one case. Variable kidney abnormalities were found by ultrasound in all of the cases, with bilateral or unilateral hyperechogenic kidneys being the most common findings. This study indicates that a strikingly high correlation between prenatal hyperechogenic kidneys and 17q12 deletion, and prenatal testing with CMA should be offered to the foetal cases of hyperechogenic kidneys. Impact statement What is already known on this subject? 17q12 deletion syndrome is a cause of renal abnormalities, maturity-onset diabetes of the young and neurodevelopmental disorders. Prenatal diagnosis has been reported in several isolated cases with the use of microarray-based technologic means. What do the results of this study add? The results provide further evidence that a strikingly high correlation between prenatal hyperechogenic kidneys and 17q12 deletion, and genetic testing should be offered to foetal cases with hyperechogenic kidneys. A rare prenatal case of 17q12 deletion with multiple structural malformations and anhydramnios is presented. What are the implications of these findings for clinical practice and/or further research? There should be a high index of suspicion of carriers in parents when 17q12 deletion is confirmed prenatally. An extremely wide phenotype spectrum of this deletion should be emphasised in the prenatal counselling.