The extreme genetic heterogeneity of nonsyndromic hearing loss (NSHL) makes genetic diagnosis expensive and time consuming using available methods. To assess the feasibility of targetenrichment and massively parallel sequencing technologies to interrogate all exons of all genes implicated in NSHL, we tested nine patients diagnosed with hearing loss. Solid-phase (NimbleGen) or solution-based (SureSelect) sequence capture, followed by 454 or Illumina sequencing, respectively, were compared. Sequencing reads were mapped using GSMAPPER, BFAST, and BOWTIE, and pathogenic variants were identified using a custom-variant calling and annotation pipeline (ASAP) that incorporates publicly available in silico pathogenicity prediction tools (SIFT, BLOSUM, Polyphen2, and Align-GVGD). Samples included one negative control, three positive controls (one biological replicate), and six unknowns (10 samples total), in which we genotyped 605 single nucleotide polymorphisms (SNPs) by Sanger sequencing to measure sensitivity and specificity for SureSelect-Illumina and NimbleGen-454 methods at saturating sequence coverage. Causative mutations were identified in the positive controls but not in the negative control. In five of six idiopathic hearing loss patients we identified the pathogenic mutation. Massively parallel sequencing technologies provide sensitivity, specificity, and reproducibility at levels sufficient to perform genetic diagnosis of hearing loss.deafness | genomics | Usher syndrome | diagnostics | next-generation sequencing H ereditary sensorineural hearing loss (SNHL) is the most common sensory impairment in humans (1, 2). In developed countries, two-thirds of prelingual-onset SNHL is estimated to have a genetic etiology, of which ∼70% is nonsyndromic hearing loss (NSHL). Eighty percent of NSHL is autosomal recessive nonsyndromic hearing loss (ARNSHL), ∼20% is autosomal dominant (AD), and the remainder is composed of X-linked and mitochondrial forms (1, 3). To date, 134 deafness loci have been identified, and 32 recessive (DFNB), 23 dominant (DFNA) and 2 X-linked (DFNX) genes have been cloned; 8 genes are associated with both ARNSHL and ADNSHL (4).Establishing a genetic diagnosis of NSHL is a critical component of the clinical evaluation of deaf and hard-of-hearing persons and their families. If a genetic cause of hearing loss is determined, it is possible to provide families with prognostic information, recurrence risks, and improved habilitation options. For persons diagnosed with Usher syndrome, preventative measures including sunlight protection and vitamin therapy can be implemented to minimize the rate of progression of retinitis pigmentosa (5). Most current genetic testing strategies for NSHL rely on a gene-specific Sanger sequencing approach. Because mutations in a single gene, GJB2 (DFNB1), account for up to 50% of ARNSHL in many world populations (6), this approach has changed the evaluation of patients with presumed ARNSHL. However, the mutation frequency in other genes in persons with NSHL in outbred populat...