In 4 Palestinian Orthodox Christian families with hearing loss linked to the DFNB28 region, Shahin et al. (2006) found a nonsense mutation in the TRIOBP gene, arg347 to ter (R347X; 609761.0001), in homozygosity in all affected individuals. Three ... In 4 Palestinian Orthodox Christian families with hearing loss linked to the DFNB28 region, Shahin et al. (2006) found a nonsense mutation in the TRIOBP gene, arg347 to ter (R347X; 609761.0001), in homozygosity in all affected individuals. Three other Palestinian Muslim families whose deafness mapped to the DFNB28 region carried another termination mutation in TRIOBP (Q581X; 609761.0002). One family was found in which 2 deaf children were compound heterozygous for R347X and Q581X. They also found a novel missense mutation in compound heterozygosity with the R347X mutation in a child with profound hearing loss. Riazuddin et al. (2006) sequenced all exons of the TRIOBP gene in genomic DNA of affected persons from each of the 12 Pakistani and Indian families identified by them. They identified 6 mutations, including 4 nonsense and 2 frameshift, in 7 families. All these mutations were located in exon 6 of the TRIOBP gene, and all 6 alleles resulted in truncation of the protein. In 5 families no mutation in TRIOBP was found, indicating the presence of additional exons of the TRIOBP gene, undetected mutations, or locus heterogeneity.