Elucidation of repeat motifs R1- and R2-related TRIOBP variants in autosomal recessive nonsyndromic hearing loss DFNB28 among indigenous South African individuals.

While a single intact R1 motif may be adequate for actin-binding and bundling in the stereocilia of cochlear hair cells, our findings indicate that a truncated R2 motif in cis seems to be incompatible with normal hearing, either by interfering with the function of an intact R1 motif or through another as yet unknown mechanism. Our study also suggests that most heterozygous missense variants involving exon 7 are likely to be tolerated.