Women with fetal multicystic dysplastic kidneys (MCDK) are commonly referred for genetic counseling, for which identification of the correct etiology is a prerequisite.Methods
A total of 72 women with fetal MCDK at Guangzhou Women and Children's Medical Center were examined via invasive prenatal diagnosis from May 2010 to June 2015. Standard karyotyping analysis was provided to all fetuses, and chromosomal microarray with Affymetrix CytoSan HD arrays was offered to cases whose DNA samples were available.Results
Abnormal karyotypes were detected in 3 of 72 (4.17%) fetuses. Of the 69 (95.8%, 69/72) fetuses with normal karyotypes, 30 (42%, 30/69) underwent chromosome microarray analysis (CMA) testing. The CMA identified pathogenic copy number variations in five fetuses, leading to a pathogenic detection rate of 16.7% (5/30). Well-known microdeletion or microduplication syndromes including renal cysts and diabetes (RCAD) syndrome and Williams–Beuren syndrome (WBS) were identified in three cases. Moreover, four chromosomal imbalanced regions were also identified in our MCDK fetuses: 22q11.1 duplication, 4q35.2 deletion, 22q13.33 duplication and 1p33 duplication. Genes PEX26, ELN, HNF1B, ALG12, FRG1, FRG2 and CYP4A11 were possible candidates for fetal MCDK. The proportions of variants of unknown significance before and after parental analysis were 13.3% (4/30) and 3.3% (1/30), respectively.Conclusions
In the present study, the frequency of chromosomal abnormalities in MCDK fetuses was 4.17% and all rearrangements were imbalanced aberrations. CMA was able to increase the pathogenic detection rate to 16.7% in MCDK fetuses with normal karyotype. Critical regions for RCAD syndrome, WBS and copy number variants of 22q11.1 duplication, 4q35.2 deletion, 22q13.33 duplication and 1p33 duplication were associated with fetal MCDK. Genes PEX26, ELN, HNF1B, ALG12, FRG1, FRG2 and CYP4A11 were possible candidates for fetal MCDK.