This study investigated the clinical and genetic characteristics of developmental disorders (DDs) in children attending a rehabilitation department. A total of 94 children with suspected rare and undiagnosed DDs were included in this study. All patients were subjected to next-generation sequencing by means of proband single whole-exome sequencing (Pro-WES) or trio whole-exome sequencing (Trio-WES). To investigate the copy number variations (CNVs), 63 patients were subjected to the trio strategy, and 17 cases were subjected to the proband single strategy. The patients developed early and suffered from severe symptoms. WES reached a high diagnostic rate (48.7%, 46/94), and de novo (48.3%, 28/58) was the main pathogenic form. Most identified single-nucleotide variations (SNVs)/small insertions and deletions (indels) were found only in one patient. The number of uncertain significant locus in the patients taking Trio-WES was significantly lower than that in patients taking Pro-WES (2.1% vs 2.8%). Compared with hereditary mutations passed from parents, pathogenicity was more obvious in de novo mutations. The diagnostic rate of WES accompanied by CNVseq (57.5%, 46/80) was significantly higher (p = 0.016) than WES alone. Next-generation sequencing exhibited a satisfactory diagnostic rate for DDs patients in the rehabilitation department. Compared with the proband-only model, the family trio strategy should be employed more frequently because it can reduce the number of uncertain significant sites and help to identify de novo pathogenic mutations.
Keywords: Copy number variation sequencing; Developmental disorders; Next-generation sequencing; Rehabilitation department; Whole-genome sequencing.