[Analysis of pathogenic variant carriage for MYO7A, PCDH15, and CDH23 genes among newborns based on high-throughput sequencing technique].

OBJECTIVE

To analyze the carrier rates and profiles of pathogenic and likely pathogenic variants for hearing loss-related genes MYO7A, PCDH15, and CDH23 among neonates in Nanjing city through targeted next-generation sequencing (NGS).

METHODS

Heel-prick blood samples were collected from 30 043 newborns delivered at Nanjing Women and Children's Health Care Hospital between March 2022 and April 2024. Dried blood spots were prepared, and genomic DNA was extracted. Targeted NGS was applied to detect variants across the full coding regions of the MYO7A, PCDH15, and CDH23 genes. The carrier rates and profiles of pathogenic and likely pathogenic variants of the three genes were analyzed. This study was approved by the Medical Ethics Committee of Nanjing Maternal and Child Health Care Hospital (Ethics No.: 2021KY-071).

RESULTS

The carrier rates of pathogenic and likely pathogenic variants (with ≥ 1 variant site) for the MYO7A, PCDH15, and CDH23 genes were 0.340%, 0.226%, and 0.156%, respectively. A total of 65, 49, and 30 variant types were detected in the MYO7A, PCDH15, and CDH23 genes, respectively. For MYO7A, single base variants were predominant, with the most common variant being c.5581C>T, followed by c.1343+1G>A, c.2837T>G, and c.5660C>T, with allelic frequencies of 0.013% (8/60 086), 0.007% (4/60 086), 0.007% (4/60 086), and 0.007% (4/60 086), respectively. PCDH15 variants were mainly deletions, with the most common variant site being c.4699_4715dupAGAGAAAAGATTCAGAG, followed by c.3441delA, c.440T>G, and c.4733_4736delTCAG, with allelic frequencies of 0.015% (9/60 086), 0.005% (3/60 086), 0.005% (3/60 086), and 0.005% (3/60 086), respectively. For CDH23, single base variants were predominant, with c.6604G>A being the most common, followed by c.6085C>T, c.6050+9G>A, and c.6253+1G>A, with allelic frequencies of 0.013% (8/60 086), 0.012% (7/60 086), 0.005% (3/60 086), and 0.005% (3/60 086).

CONCLUSION

This study analyzed the carrier rates and profiles of pathogenic and likely pathogenic variants of the MYO7A, PCDH15, and CDH23 genes, which can provide more evidence for the prevention and management of deafness in the region.