[Analysis of perrault syndrome caused by pathogenic variants in LARS2 and HARS2 genes]

Objective: To investigate the molecular etiology of Perrault syndrome by analyzing the clinical phenotype and pathogenic gene variants of 2 male patients with bilateral severe sensorineural deafness. Methods: Two male patients with Perrault syndrome characterized by severe sensonrineual deafness adimitted to the First Affiliated Hospital of Zhengzhou University between February 2021 and March 2022 were selected, and the clinical phenotype and pathogenic gene variants of them and their family members were summarized. The whole exome sequencing technology was used to screen the pathogenic variants of the probands, and the candidate variants were determined by combining with clinical phenotype. The probands and their family members were verified by the Sanger sequencing method. Results: The whole exome sequencing results showed that the proband of family 1 had a compound heterozygous variants of the LARS2 (NM_015340.4) gene c.1565C>A (p.Thr522Asn) and c.1079T>C (p.Ile360Thr). The reported pathogenic variant c.1565C>A came from the mother, and the novel variant c.1079T>C came from the father. The second proband harbored compound heterozygous variants of HARS2 gene (NM_012208.4) c.1273C>T (p.Arg425Trp) and c.1403G>C (p.Gly468Ala), with the former from the proband's mother, the latter from the father. The c.1273C>T was novel and c.1403G>C was the reported pathogenic variant. All above variants were respectively classified as pathogenic, uncertain significance, uncertain significance and likely pathogenic based on the ACMG guidelines. Conclusion: This study expands the mutational spectrum of LARS2 and HARS2 genes, which highlights that genetic testing plays an important role in the early diagnosis of syndromic deafness.