Mutations in CLDN14 are associated with different hearing thresholds

Mutations in CLDN14, encoding tight junction protein claudin 14, cause profound deafness in mice and humans. We identified a Pakistani family, in which the affected individuals were homozygous for a known pathogenic mutation c.254 T>A resulting in p.V85D substitution in CLDN14; however, in contrast to the previously reported families with mutations in CLDN14, most of the affected individuals in this family exhibit only a severe hearing loss (HL). In order to identify the contribution of CLDN14 to less than profound deafness, we screened for mutations of CLDN14 in 30 multiplex and 57 sporadic cases with moderately severe to severe HL from Pakistan. We identified one other affected individual homozygous for p.V85D substitution. Comparison of audiometric data from all patients indicates that mutations in CLND14 cause varying degrees of HL, which may be enhanced at high frequencies. This suggests that a modifier can reduce the severity of HL associated with mutations of CLDN14. Our data indicate that mutations in CLDN14 should be explored when considering the etiology of less severe HL.