Case report of a novel mutation in the TNC gene in Chinese patients with nonsyndromic hearing loss.

Rationale: Hereditary hearing loss is known to exhibit a significant degree of genetic heterogeneity. Herein, we present a case report of a novel mutation in the tenascin-C (TNC) gene in Chinese patients with nonsyndromic hearing loss (NSHL).

Patient Concerns: This includes a young deaf couple and their 2-year-old baby.

Diagnoses: Based on the clinical information, hearing test, metagenomic next-generation sequencing (mNGS), Sanger sequencing, protein function and structure analysis, and model prediction, in our case, the study results revealed 2 heterozygous mutations in the TNC gene (c.2852C>T, p.Thr951Ile) and the TBC1 domain family member 24 (TBC1D24) gene (c.1570C>T, p.Arg524Trp). These mutations may be responsible for the hearing loss observed in this family. Notably, the heterozygous mutations in the TNC gene (c.2852C>T, p.Thr951Ile) have not been previously reported in the literature.

Interventions: Avoid taking drugs that can cause deafness, wearing hearing AIDS, and cochlear implants.

Outcomes: Regular follow-up of family members is ongoing.

Lessons: The genetic diagnosis of NSHL holds significant importance as it helps in making informed treatment decisions, providing prognostic information, and offering genetic counseling for the patient's family.