[Phenotypic and pathogenic variant analysis of an X-linked dominant inherited non-syndromic hearing loss pedigree].

Objective

X-linked non-syndromic hearing loss is an extremely rare type of hearing impairment. This study conducted a phenotypic and genetic analysis of a family with X-linked dominant inheritance to explore the causes of hearing loss.

Methods

Clinical data were collected from a patient with non-syndromic hearing loss who visited the Otorhinolaryngology Department of the First Affiliated Hospital of Zhengzhou University in June 2023. Phenotypic and genetic analyses were performed on family members, including audiometric tests, whole-exome sequencing, and PCR-Sanger sequencing verification. Audiological assessments comprised pure-tone audiometry, impedance audiometry, auditory brainstem response, and otoacoustic emission tests.

Results

The affected individuals in this pedigree have X-linked dominant non-syndromic deafness caused by mutations in the SMPX gene. The proband, along with their mother and maternal grandmother, exhibit varying degrees of sensorineural hearing loss. Whole-exome sequencing revealed a novel pathogenic variant, NM_014332.3: c. 133-2A>C, in the SMPX gene in the proband. Sanger sequencing confirmed that the proband, proband's mother, and grandmother all carried this pathogenic variant.

Conclusion

This study reports a novel pathogenic variant in the SMPX gene, providing additional medical evidence for the diagnosis and treatment of X-linked dominant inherited non-syndromic hearing loss. It enriches the mutation spectrum of the SMPX gene.