[Prenatal diagnosis of 17q12 microdeletion syndrome in fetal renal abnormalities]

Objectives: To analyze 3 cases of 17q12 microdeletion syndrome diagnosed prenatally, and to demonstrate clinical phenotype of the syndrome in prenatal setting. Methods: From January 2013 to July 2017, 1 370 women received invasive prenatal diagnosis and chromosome microarray analysis (CMA) in Peking Union Medical College Hospital. Among them, 3 fetuses were diagnosed as 17q12 microdeletion syndrome. All 3 cases were low-risk pregnancies. Abnormal structures in fetal kidney were found in all 3 cases, including 1 case of multiple renal cysts, 2 cases of bilateral hyperechogenic kidneys. These women accepted invasive prenatal diagnosis followed by karyotyping, parental fluorescence in situ hybridization or CMA validation. Results: The second and third trimester ultrasound showed that all 3 fetuses had bilateral renal structural abnormalities, including hyperechogenic kidney, multiple cysts and renal pelvis dilatation. The karyotyping of the 3 fetuses were normal. CMA examination showed that each case had 1.4-1.6 Mb deletion in 17q12 region. Two cases were de novo deletion and 1 case was inherited from the mother who had mild symptoms. The 3 women decided to terminate pregnancies after genetic counseling. Conclusion: 17q12 microdeletion syndrome is a recurrent chromosome microdeletion syndrome, and the unique phenotype in prenatal setting is the abnormal structure of bilateral kidneys. A few cases of 17q12 microdeletion syndrome even inherited normally phenotypical parents, and prenatal genetic counseling of 17q12 microdeletion syndrome is relatively difficult.