Koleilat, Alaa

PurposeMore than 460 million people suffer from disabling hearing loss worldwide, and about 50%–60% of hearing loss in infants are due to genetics. Usher syndrome is a genetic condition in which children are born deaf or hard of hearing and subsequently develop retinitis pigmentosa. It is the most common cause of deafness and blindness in pediatric populations, and pathogenic variants in 10 different genes are shown to be causative. The purpose of this review article is to advance the understanding of the clinical symptoms of an individual with Usher syndrome and highlight the latest research in the development of new treatments including gene therapy. The care and management of individuals with Usher syndrome require a team of multidisciplinary health care professionals, including an audiologist, a speech-language pathologist, an ophthalmologist, and a medical geneticist. We highlight the importance of early identification for better speech and developmental outcomes, specifically in pediatric individuals.ConclusionThis review empowers audiologists to be aware of early signs of Usher syndrome as they are typically the first point of contact and provides important information for audiologists and other health care professionals involved in the care of individuals with hearing loss and vision loss.

Customizable endonucleases such as transcription activator-like effector nucleases (TALENs) and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) enable rapid generation of mutant strains at genomic loci of interest in animal models and cell lines. With the accelerated pace of generating mutant alleles, genotyping has become a rate-limiting step to understanding the effects of genetic perturbation. Unless mutated alleles result in distinct morphological phenotypes, mutant strains need to be genotyped using standard methods in molecular biology. Classic restriction fragment length polymorphism (RFLP) or sequencing is labor-intensive and expensive. Although simpler than RFLP, current versions of allele-specific PCR may still require post-polymerase chain reaction (PCR) handling such as sequencing, or they are more expensive if allele-specific fluorescent probes are used. Commercial genotyping solutions can take weeks from assay design to result, and are often more expensive than assembling reactions in-house. Key components of commercial assay systems are often proprietary, which limits further customization. Therefore, we developed a one-step open-source genotyping method based on quantitative PCR. The allele-specific qPCR (ASQ) does not require post-PCR processing and can genotype germline mutants through either threshold cycle (C t ) or end-point fluorescence reading. ASQ utilizes allele-specific primers, a locus-specific reverse primer, universal fluorescent probes and quenchers, and hot start DNA polymerase. Individual laboratories can further optimize this open-source system as we completely disclose the sequences, reagents, and thermal cycling protocol. We have tested the ASQ protocol to genotype alleles in five different genes. ASQ showed a 98–100% concordance in genotype scoring with RFLP or Sanger sequencing outcomes. ASQ is time-saving because a single qPCR without post-PCR handling suffices to score genotypes. ASQ is cost-effective because universal fluorescent probes negate the necessity of designing expensive probes for each locus.