Application of copy number variation sequencing in patients with intellectual disability/developmental delay and autistic spectrum disorder / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of copy number variation sequencing (CNV-seq) for the diagnosis of children with intellectual disability (ID), developmental delay (DD), and autistic spectrum disorder (ASD).@*METHODS@#Forty patients with ID/DD/ASD referred to Nanshan Maternity and Child Health Care Hospital from September 2018 to January 2022 were enrolled. G-banded karyotyping analysis was carried out for the patients. Genomic DNA was extracted from peripheral blood samples and subjected to CNV-Seq analysis to detect chromosome copy number variations (CNVs) in such patients. ClinVar, DECIPHER, OMIM and other database were searched for data annotation.@*RESULTS@#Among the 40 patients (including 30 males and 10 females), 16, 15 and 6 were diagnosed with ID, DD and ASD, respectively. One patient had combined symptoms of ID and DD, whilst the remaining two had combined ID and ASD. Four patients were found with abnormal karyotypes, including 47,XY,+mar, 46,XY,inv(8)(p11.2q21.2), 46,XX,del(5)(p14) and 46,XX[76]/46,X,dup(X)(p21.1q12). Chromosome polymorphism was also found in two other patients. CNV-seq analysis has detected 32 CNVs in 20 patients (50.0%, 20/40). Pathogenic CNVs were found in 10 patients (25.0%), 15 CNVs of uncertain clinical significance were found in 12 patients (30.0%), and 7 likely benign CNVs were found in 4 patients (10.0%).@*CONCLUSION@#Chromosome CNVs play an important role in the pathogenesis of ID/DD/ASD. CNV-seq can detect chromosomal abnormalities including microdeletions and microduplications, which could provide a powerful tool for revealing the genetic etiology of ID/DD/ASD patients.

Analysis of results of concurrent hearing and deafness genetic screening and follow up of 33 911 newborns / 中华医学遗传学杂志

OBJECTIVE@#To analyze the results of concurrent hearing and deafness genetic screening and follow up of newborns.@*METHODS@#In total 33 911 babies born to 5 designated hospitals in Nanshan District of Shenzhen city from October 2017 to December 2019 were included. All subjects underwent concurrent hearing and deafness genetic screening covering 21 variants of 4 genes including GJB2, SLC26A4, GJB3 and Mt12SrRNA. For those with positive results, Sanger sequencing was carried out for confirmation.@*RESULTS@#93.32% subjects passed the first-round hearing screening, and 87.01% passed the recheck testing. The overall detection rate was 4.18%. The detection rates for GJB2, SLC26A4, GJB3 and Mt12srRNA variants were 1.98%, 1.58%, 0.37% and 0.25%, respectively. 126 and 84 subjects were found with high risk for delayed-onset and drug-induced hearing loss, respectively. In addition, 4 and 5 subjects were found to harbor homozygous/compound heterozygous variants of the GJB2 and SLC26A4 genes, respectively. Concurrent screening showed that subjects (with heterozygous variants) who did not passed the two round hearing test were as follows: GJB2 with 6.75% in the first round and 2.61% in the second round testing, SLC26A4 (3.3%/1.2%), GJB3 (0.72%/0.14%) and 12SrRNA (0.36%/Nil), respectively. Moreover, the No-pass rate in the subjects with homozygous or compound variants in single gene, heterozygous variant in single gene, heterozygous variant in multiple genes, and homozygous variant in GJB3 gene were significantly higher than the subjects with negative results of genetic screening.@*CONCLUSION@#Concurrent newborn genetic screening can enhance the effectiveness of hearing screening and enable earlier identification and intervention for children with hearing impairment. Follow-up can improve the diagnostic rate for children who are positive for the concurrent screening. Nevertheless, genetic and hearing screening cannot replace the diagnostic testing. It is necessary to conduct comprehensive analysis for the results of genetic and hearing screening and radiological examinations. Sanger sequencing and next-generation sequencing are critical for ascertain the diagnosis.