A new syndromic case of hearing loss and ectodermal anomalies associated with a recurrent missense variation in GJB6 gene.

GJB2 and GJB6 variants, encoding Cx26 and Cx30 respectively, are the most frequently involved genes commonly contributing to hereditary hearing loss either isolated or in combination with skin abnormalities. GJB6 variations are classically associated with two distinct conditions: non-syndromic hearing loss and hidrotic ectodermal dysplasia, type Clouston, the latter typically not involving deafness.

Method: Whole genome sequencing (WGS) was used to find genetic variants after clinical features of a 13-year-old female patient were recorded.

Results: In this report, we describe the association of congenital hearing loss and ectodermal anomalies (palmoplantar keratoderma, knuckle pads, and nail dystrophy) in a female with the ENST00000647029.1 (GJB6): c.175G>A (p.(Gly59Arg)) GJB6 variant. As a result, we report on the third case of individuals showing this same missense variant and syndromic hearing loss.

Conclusion: This study underscores the overlapping phenotypes observed in patients with the p.Gly59Arg variant in the GJB6 gene. The findings suggest a continuum of phenotypic presentations for this variant, with the key clinical features being the combination of congenital hearing loss and hyperkeratosis.