Project description:Objectives: Despite recent advancements in diagnostic tools, the genomic landscape of hereditary hearing loss remains largely uncharacterized. One strategy to understand genome-wide aberrations includes the analysis of copy number variation that can be mapped using SNP-microarray technology. A growing collection of literature has begun to uncover the importance of copy number variation in hereditary hearing loss. This pilot study underpins a larger effort that involves the stage-wise analysis of hearing loss patients, many of whom have advanced to high-throughput sequencing analysis. Data description: Our data originate from Infinium HumanOmni1-Quad v1.0 SNP-microarrays (Illumina) that provide useful markers for genome-wide association studies and copy number variation analysis. This dataset comprises a cohort of 108 individuals (99 with hearing loss, 9 normal hearing family members) for the purpose of understanding the genetic contribution of copy number variations to hereditary hearing loss.
Project description:Background The genetic diversity of loci and mutations underlying hereditary hearing loss is an active area of investigation. To identify loci associated with predominantly non-syndromic sensorineural hearing loss, we performed exome sequencing of families and of single probands, as well as copy number variation (CNV) mapping in a case-control cohort. Results Analysis of three distinct families revealed several candidate loci in two families and a single strong candidate gene, MYH7B, for hearing loss in one family. MYH7B encodes a Type II myosin, consistent with a role for cytoskeletal proteins in hearing. High-resolution genome-wide CNV analysis of 150 cases and 157 controls revealed deletions in genes known to be involved in hearing (e.g. GJB6, OTOA, and STRC, encoding connexin 30, otoancorin, and stereocilin, respectively), supporting CNV contributions to hearing loss phenotypes. Additionally, a novel region on chromosome 16 containing part of the PDXDC1 gene was found to be frequently deleted in hearing loss patients (OR = 3.91, 95% CI: 1.62-9.40, p = 1.45 x 10-7). Conclusions We conclude that many known as well as novel loci and distinct types of mutations not typically tested in clinical settings can contribute to the etiology of hearing loss. Our study also demonstrates the challenges of exome sequencing and genome-wide CNV mapping for direct clinical application, and illustrates the need for functional and clinical follow-up as well as curated open-access databases. Single replicates of 151 non-syndromic hereditary hearing loss cases and 157 controls with normal hearing were analyzed.
Project description:Background The genetic diversity of loci and mutations underlying hereditary hearing loss is an active area of investigation. To identify loci associated with predominantly non-syndromic sensorineural hearing loss, we performed exome sequencing of families and of single probands, as well as copy number variation (CNV) mapping in a case-control cohort. Results Analysis of three distinct families revealed several candidate loci in two families and a single strong candidate gene, MYH7B, for hearing loss in one family. MYH7B encodes a Type II myosin, consistent with a role for cytoskeletal proteins in hearing. High-resolution genome-wide CNV analysis of 150 cases and 157 controls revealed deletions in genes known to be involved in hearing (e.g. GJB6, OTOA, and STRC, encoding connexin 30, otoancorin, and stereocilin, respectively), supporting CNV contributions to hearing loss phenotypes. Additionally, a novel region on chromosome 16 containing part of the PDXDC1 gene was found to be frequently deleted in hearing loss patients (OR = 3.91, 95% CI: 1.62-9.40, p = 1.45 x 10-7). Conclusions We conclude that many known as well as novel loci and distinct types of mutations not typically tested in clinical settings can contribute to the etiology of hearing loss. Our study also demonstrates the challenges of exome sequencing and genome-wide CNV mapping for direct clinical application, and illustrates the need for functional and clinical follow-up as well as curated open-access databases.
Project description:Next-Generation Sequencing techniques (i.e, targeted re-sequencing and whole exome sequencing) have been employed for the study of two Italian patients affected by age-related hearing loss and of an Italian family affected by hereditary hearing loss. Data analysis led to the identification of three variants in SPATC1L, associated with the clinical phenotype.
Project description:Mutations in GJB2 (Gap junction protein beta 2) are the most common genetic cause of non-syndromic hereditary deafness in humans, especially the 35delG and 235delC mutations. Owing to the homozygous-lethal of Gjb2 mutation in mice, there are currently no perfect mouse models carrying Gjb2 mutation to mimic human hereditary deafness and unveil the pathogenesis. Here, we first constructed heterozygous mutant mice, Gjb2+/35delG and Gjb2+/235delC, through androgenic haploid embryonic stem cells (AG-haESCs) mediated semi-cloning technology, which showed normal hearing function at P28. Furthermore, a homozygous mutant mouse model, Gjb235delG/35delG, was generated via enhanced tetraploid embryo complementation, which exhibited profound hearing loss like human patients at P14. Mechanism analysis showed that Gjb2 35delG disrupts the formation of intercellular gap junction channel and tunnel of Corti, and hair cell mechanotransduction, rather than the development of hair cells. Collectively, our study provides ideal mouse models for understanding the pathogenic mechanism and opens up a new avenue for investigating the treatment for DFNB1A-related hereditary deafness.
Project description:Hearing loss is one of the most prevalent sensory disorders, but no commercial biological treatments are currently available. Here, we identify an East Asia-specific founder mutation, the homozygous c.220C>T mutation in MPZL2, that contributes to a significant proportion of hereditary deafness cases in our cohort study. We find that the disease-causing mutation can be targetable by adenine base editors (ABEs) that enable A·T-to-G·C base corrections without DNA double-strand breaks. To demonstrate this, we develop a humanized mouse model (hMPZL2Q74X/Q74X) that recapitulates human MPZL2 deafness and leads to progressive hearing loss. A PAM-flexible ABE variant with reduced bystander and off-target effects (ABE8eWQ-SpRY:sgRNA3) is packaged in dual adeno-associated viruses (AAVs) and injected into the inner ear of hMPZL2Q74X/Q74X mice and effectively corrects the mutation. This treatment significantly restores hearing function, improves inner ear structural integrity, and reverses altered gene expression. Base editing may hold therapeutic potential for hereditary deafness, including most cases of MPZL2 deafness.
Project description:Gene expression profiling of apical and basal halves of the spiral ganglion of hearing and kanamycin-deafened rats at P32 and P60 was performed using microarray analysis. The data are further described in Rahman MT, Bailey EM, Gansemer BM, Pieper AA, Manak JR, and Green SH. Anti-inflammatory compounds improve spiral ganglion neuron survival after aminoglycoside-induced hair cell loss in rats.
Project description:Presbycusis – age-related hearing loss – is the number one communicative disorder of our aged population. Here we analyzed gene expression for a set of GABA receptors in the cochlea of aging CBA mice using the Affymetrix GeneChip MOE430A. Functional phenotypic hearing measures distortion-product otoacoustic emission (DPOAE) amplitudes (four age groups) were made. The gene expression changes from RMA normalized microarray data (40 replicates) were first subjected to one-way ANOVA, and then linear regression was performed. In addition, the log signal ratio was converted to fold change, and selected gene expression changes were confirmed by relative real-time PCR. Major findings: expression of GABA-A receptor subunit 6was upregulated with age and hearing loss, whereas subunit 1 was repressed. In addition, GABA-A receptor associated protein like-1 and GABA-A receptor associated protein like-2 were strongly downregulated with age and hearing impairment. Lastly, gene expression measures were correlated with pathway/network relationships relevant to the inner ear using Pathway Architect, to identify key pathways consistent with the gene expression changes observed. In the study of expression changes GABA receptors in the in cochlea of young adult and aging presbycusis mice total of forty chips were used. The normal aging mice were in four groups young adults controls with good hearing (8 mice, 8 MOE430A GeneChips), Middle aged group with good hearing ( 17 mice, 17 MOE430A GeneChips), Mild Presbycusis (old) with limited hearing loss (9 mice, 9 MOE430A GeneChips) and Severe Presbycusis (old) (6 mice, 6 MOE430A GeneChips). Each Mice cochlea to each GeneChips, Samples was not pooled. The hearing potential evidence of each mouse is accompanied with each mice DPOAE amplitude.