[Prenatal utility of parental source verification on the interpretation of copy number variation identified by...

To investigate the parental-origin verification of fetal CNVs in the setting of prenatal diagnosis.

182 families were recruited in this study. All the pregnant women underwent transabdominal amniocentesis or cordocentesis, and the amniotic fluid or cord blood samples were then subjected to karyotyping and chromosomal microarray analysis (CMA) respectively. The peripheral blood specimens of fetal parents were also tested by CMA for determining the parental-origin of fetal CNVs. Then we followed up the clinical outcomes of the fetuses.

Of the 182 fetuses, 163 (89.6%) had parental-origin CNVs, and 19 (10.4%) had de novo CNVs. 149 (91.4%) of the parental-origin CNVs were classified into the variant of uncertain significance (VUS) before parental-origin tests. After parental source verification, 137 (91.9%) of these VUS cases were changed into likely benign cases. Among the 163 cases of parental-origin CNVs, 122 (74.8%) fetuses were born healthy. Among the 19 de novo cases, 9 of these families chose to terminate the pregnancy.

The majority of inherited CNVs detected by CMA had a tendency to be benign, and the parental source verification could assist the elucidation of clinical significance of CNVs in prenatal diagnosis.