Prenatal Diagnosis of Microduplication of Fetal Chromosome 17 Following Noninvasive Prenatal Testing

Abstract Background Chromosome 17q12 duplication syndrome is a disease caused by the complete or partial duplication of q12 in the long arm of chromosome 17, there were no cases reported about the prenatal diagnosis of the syndrome. Most of the fetal phenotype of the syndrome may not be evident during the pregnancy, which means the syndrome was only be discovered accidentally or missed during the prenatal examination. Objective Noninvasive prenatal testing (NIPT) is widely used in the screening of common fetal chromosome aneuploidy. However, reports on chromosomal microduplication and microdeletion are rare. The aim of the study was to investigate the application value of NIPT for the detection of chromosomal microduplication. Case presentations: We found two cases of microduplication in the long arm of chromosome 17(17q12), they were first detected by NIPT and then were further diagnosed by copy number variation (CNV) analysis based on chromosome microarray analysis (CMA). The CMA results of prenatal diagnosis showed that the microduplications in 17q12 (one was 1.5Mb, the other was 1.9Mb) were consistent with the NIPT results. The amniotic fluid karyotype analysis showed no abnormalities. Finally, because it was pathogenic copy number variant, both of the parents chose to terminate the pregnancy. Conclusion In the study, two cases of microduplication fragment in the long arm of chromosome 17 were detected by NIPT and were confirmed by CMA. To our knowledge, this is the first report of prenatal diagnosis of chromosome 17q12 duplication syndrome following NIPT. This suggests that NIPT is an effective method to screen chromosome microduplications in prenatal diagnosis, especially for the chromosome 17q12 duplication syndrome.