Background: Array comparative genomic hybridization (aCGH), karyotyping and fluorescence in situ hybridization (FISH) analyses have been used in a clinical cytogenetic laboratory. A systematic analysis on diagnostic findings of cytogenomic abnormalities in current prenatal and pediatric settings provides approaches for future improvement. Methods: A retrospective analysis was performed on abnormal findings by aCGH, karyotyping, and FISH from 3,608 prenatal cases and 4,509 pediatric cases during 2008-2017. The diagnostic accuracy was evaluated by comparing the abnormality detection rate (ADR) and the relative frequency (RF) of different types of cytogenomic abnormalities between prenatal and pediatric cases. A linear regression correlation between known prevalence and ADR of genomic disorders was used to extrapolate the prevalence of other genomic disorders. The diagnostic efficacy was estimated as percentage of detected abnormal cases by expected abnormal cases from served population. Results: The composite ADR for numerical chromosome abnormalities, structural chromosome abnormalities, recurrent genomic disorders, and sporadic pathogenic copy number variants (pCNVs) in prenatal cases were 13.03%, 1.77%, 1.69%, and 0.9%, respectively, and were 5.13%, 2.84%, 7.08%, and 2.69% in pediatric cases, respectively. The chromosomal abnormalities detected in prenatal cases (14.80%) were significantly higher than that of pediatric cases (7.97%) (p < 0.05), while the pCNVs detected in prenatal cases (2.59%) were significantly lower than that of pediatric cases (9.77%) (p < 0.05). The prevalence of recurrent genomic disorders and total pCNVs was estimated to be 1/396 and 1/291, respectively. Approximately, 29% and 35% of cytogenomic abnormalities expected from the population served were detected in current prenatal and pediatric diagnostic practice, respectively. Conclusion: For chromosomal abnormalities, effective detection of Down syndrome (DS) and Turner syndrome (TS) and under detection of sex chromosome numerical abnormalities in both prenatal and pediatric cases were noted. For pCNVs, under detection of pCNVs in prenatal cases and effective detection of DiGeorge syndrome (DGS) and variable efficacy in detecting other pCNVs in pediatric cases were noted. Extend aCGH analysis to more prenatal cases with fetal ultrasonographic anomalies, enhanced non-invasive prenatal (NIPT) testing screening for syndromic genomic disorders, and better clinical indications for pCNVs are approaches that could improve diagnostic yield of cytogenomic abnormalities.

Bombyx mori bidensovirus (BmBDV) of the family Bidnaviridae is the unique animal multipartite virus until now, which contains two-segmented linear single-stranded DNA genome VD1 (6.5 kb) and VD2 (6.0 kb). Both two segments and their complementary strands are encapsidated separately. Although the different frequencies of genome segments were reported in multipartite viruses of plants, the relative abundances of segments in the animal multipartite virus has not been studied yet. In this paper, the relative frequencies of VD1 and VD2 composing the genome of BmBDV were determined by qPCR in different samples. The results showed that the copy number of VD2 is 1.22-, 1.47-, and 1.73-fold as much as that of VD1 in purified virions, excrement of BmBDV-infected silkworm, and BmBDV-infected midguts, respectively. These results demonstrated that the various genome segments also accumulate with different frequency in BmBDV populations and the copy number of short-segment VD2 is more than that of long-segment VD1, indicating that the imbalance of segmental genome copy number is a common phenomenon in multipartite viruses of plants and animals.