[Whole exome sequencing analysis and prenatal diagnosis in children with neurodevelopmental disorders]

To explore the application value of whole exome sequencing (WES) in the diagnosis of prenatal and postnatal neurodevelopmental disorders (NDDs). A total of 70 patients diagnosed with NDDs who underwent WES at the Medical Genetics Center of the Maternal and Child Health Hospital of Hubei Province between June 2020 and July 2021 were retrospectively analyzed. Genomic DNA was extracted from peripheral blood samples and amniotic fluid. WES-based copy number variant (CNV) analysis was integrated into the routine WES data analysis pipeline. The results showed that a molecular diagnosis rate could be made in 21/70 (30%) cases. Of 21 positive cases, 14 (23%) cases were detected by single-nucleotide variant/small insertion/deletion (SNV/Indel) analysis, of which 12 variants were novel, 6 (9.8%) cases were detected by WES-based CNV analysis, and 1 (1.6%) case was detected by a combination of both. The diagnostic yield of WES combined with CNV analysis was higher than that of SNV/Indel analysis alone (30%, 21/70 vs. 20%, 14/70). Of the 28 prenatally diagnosed cases, 6 cases were found to have inherited parental variation for NDDs, 10 cases were found not to have the same pathogenic variation as the proband, and the remaining 12 cases were found to have no pathogenic or likely pathogenic variation that could explain the NDDs phenotype. Clinical follow-up showed that 5 families opted for abortion and the remaining had no current abnormalities. In conclusion, WES may be an effective method to clarify the genetic etiology and prenatal diagnosis of NDDs, which is helpful in assessing the prognosis to aid clinical management and reproductive guidance.