Prenatal diagnosis of 17q12 microdeletion and microduplication syndrome in fetuses with congenital renal abnormalities

BACKGROUND: Copy number variations (CNVs) involving the 17q12 region are associated with a broad range of clinical phenotypes. Deletion of the 17q12 chromosome results in structural or functional abnormalities in the kidney and urethra, type 5 diabetes (MODY5), and neurodevelopmental or neuropsychiatric disorders. Microduplication of 17q12 is rare and is associated with an increased risk of epilepsy and mental retardation. We studied the prenatal diagnosis of 17q12 microduplication and microdeletion syndrome in fetuses with congenital renal abnormalities. CASE PRESENTATION: We conducted a retrospective analysis of prenatal diagnoses in our hospital from January 2016 to April 2018. Abnormal renal ultrasound findings were present in 126 fetuses and the incidence of chromosomal abnormalities was 10.32%(13/126). Conventional karyotyping detected 7 of 126 fetuses as aneuploid (5.56%). In addition, chromosome microarray analysis (CMA) detected 6 fetuses(4.76%) with copy number variations (CNVs), of which 5 were shown to have 17q12 microdeletion syndrome and 1 had 17q12 microduplication syndrome. We followed up these pregnant women. The results of the testing had a significant impact on pregnancy outcome. The phenotypes of 17q12 microdeletions and microduplications vary widely, affecting patients in different ways, such as language delays, social deficiencies, and even abortion. CONCLUSIONS: The characteristics of 17q12 microdeletions and microduplications are so vague that the condition is often misdiagnosed or missed. This study demonstrated that karyotype analysis combined with CMA can significantly improve the diagnostic rate in prenatal diagnosis of CNVs, which can provide evidence for genetic counseling in such pregnancies.