The relationship between the GJB3 c.538C>T variant and hearing phenotype in the Chinese population

Mutations in GJB3 were originally shown to underlie an autosomal dominant form of non-syndromic deafness in Chinese patients and the c.538C>T (p.R180*) variants caused high-frequency hearing loss. But after that, few reports have reported this mutation. This study investigated the relationship between the GJB3 c.538C>T variant and hearing phenotype in Chinese to assist with risk assessment and genetic counseling for hearing loss patients and their families.

The study enrolled 5700 patients with hearing loss and 4600 normal subjects. Deafness gene mutations were distinguished using a gene chip. The GJB3 c.538C>T variant rate was calculated from the results.

Of the 5700 patients, 23 (0.40%) carried a GJB3 c.538C>T heterozygous variant; of these, 11 patients had other gene (GJB2/SLC26A4) mutations simultaneously. Most patients had moderate to profound hearing loss. All 23 patients were sporadic cases and had no family history of deafness. Of the 4600 normal individuals, 11 (0.24%) had GJB3 c.538C>T heterozygous variant. There was no statistical difference in incidence between the two groups.

Our results showed that the GJB3 c.538C>T variant has a very low incidence in the Chinese population, and there was no clear evidence to support a role of the GJB3 c.538C>T variant in the autosomal dominant form of non-syndromic deafness. Our findings suggested that GJB3 c.538C>T does not contribute to hearing loss, and this conclusion will assist with genetic counseling and risk prediction for deafness related to the GJB3 c.538C>T variant.