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Nonsyndromic Deafness
Nonsyndromic deafness is hearing loss that is not associated with other signs and symptoms. In contrast, syndromic deafness involves hearing loss that occurs with abnormalities in other parts of the body. Nonsyndromic deafness constitutes 75% of all hearing loss cases, and an estimated 100 genes are thought to be linked to this condition. About 80% are linked to autosomal recessive inheritance, 15% to autosomal dominant inheritance, 1-3% through the X chromosome, and 0.5-1% are associated with mitochondrial inheritance. Genetic changes are related to the following types of nonsyndromic deafness: * DFNA: nonsyndromic deafness, autosomal dominant * DFNB: nonsyndromic deafness, autosomal recessive * DFNX: nonsyndromic deafness, X-linked * nonsyndromic deafness, mitochondrial Each type is numbered in the order in which it was described. For example, DFNA1 was the first described autosomal dominant type of nonsyndromic deafness. Mitochondrial nonsyndromic deafness involves changes to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hearing Impairment
Hearing loss is a partial or total inability to Hearing, hear. Hearing loss may be present at birth or acquired at any time afterwards. Hearing loss may occur in one or both ears. In children, hearing problems can affect the ability to Language acquisition, acquire spoken language, and in adults it can create difficulties with social interaction and at work. Hearing loss can be temporary or permanent. Presbycusis, Hearing loss related to age usually affects both ears and is due to cochlear hair cell loss. In some people, particularly older people, hearing loss can result in loneliness. Hearing loss may be caused by a number of factors, including: genetics, ageing, Noise-induced hearing loss, exposure to noise, some infections, birth complications, trauma to the ear, and certain medications or toxins. A common condition that results in hearing loss is chronic ear infections. Certain infections during pregnancy, such as cytomegalovirus, syphilis and rubella, may also cause he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDH23
Cadherin-23 is a protein that in humans is encoded by the ''CDH23'' gene. Function This gene is a member of the cadherin superfamily, genes encoding calcium dependent cell-cell adhesion glycoproteins. The protein encoded by this gene is a large, single-pass transmembrane protein composed of an extracellular domain containing 27 repeats that show significant homology to the cadherin ectodomain. Expressed in the neurosensory epithelium, the protein is thought to be involved in stereocilia organization and hair bundle formation. Specifically, it is thought to interact with protocadherin 15 to form tip-link filaments. Clinical significance The gene is located in a region containing the human deafness loci DFNB12 and USH1D. Usher syndrome 1D and nonsyndromic autosomal recessive deafness DFNB12 are caused by allelic mutations of this novel cadherin-like gene. The gene is associated with kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OTOF
Otoferlin is a protein that in humans is encoded by the ''OTOF'' gene. It is involved in vesicle membrane fusion, and mutations in the OTOF gene are associated with a genetic form of deafness. Function There are two forms of otoferlin protein. The short form of the protein has three C2 domains and a single carboxy-terminal transmembrane domain found also in the ''C. elegans'' spermatogenesis factor FER-1 and human dysferlin. The long form has six C2 domains. Dysferlin and myoferlin are proteins found in humans that are homologous to otoferlin. Both dysferlin and myoferlin have seven C2 domains. A C2 domain is a protein structural domain involved in targeting proteins to cell membranes. C2A in otoferlin's longer form, with six C2 domains, is structurally similar to dysferlin C2A. However, loop 1 in the calcium (Ca2+) binding site of otoferlin C2A is significantly shorter than the homologous loop in dysferlin and myoferlin C2A domains. Therefore, it is unable to bind to cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYO7A
Myosin VIIA is protein that in humans is encoded by the ''MYO7A'' gene. Myosin VIIA is a member of the unconventional myosin superfamily of proteins. Myosins are actin binding molecular motors that use the enzymatic conversion of ATP - ADP + inorganic phosphate (Pi) to provide the energy for movement. Myosins are mechanochemical proteins characterized by the presence of a motor domain, an actin-binding domain, a neck domain that interacts with other proteins, and a tail domain that serves as an anchor. Myosin VIIA is an unconventional myosin with the longest tail (1360 aa). The tail is expected to dimerize, resulting in a two-headed molecule. Unconventional myosins have diverse functions in eukaryotic cells and are primarily thought to be involved in the movement or linkage of intra-cellular membranes and organelles to the actin cytoskeleton via interactions mediated by their highly divergent tail domains. MYO7A is expressed in a number of mammalian tissues, including testis, ki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYO6
Unconventional myosin-VI, is a protein that in humans is coded for by ''MYO6''. Unconventional myosin-VI is a myosin molecular motor involved in intracellular vesicle and organelle transport. Structure Human myosin-VI contains a N-terminal myosin head domain (residues 59–759), two coiled coil motifs (residues 902–984 and 986–1009 respectively), and a C-terminal myosin VI cargo binding domain (residues 1177–1267). Function Unconventional myosin-VI is unique because it travels in the opposite direction of other myosins, towards the negative end of actin filaments. Myosin-VI follows the same structure as other myosin but with two unique "inserts" allowing for its diversified properties. One insert is called the "reverse gear" and is responsible for its movement towards the negative end of actin filaments. The reverse gear is located on the neck region of the myosin and acts as a reorienting device for the lever arm to move backwards after myosin movement. The second inser ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MYO15A
Unconventional myosin-XV is a protein that in humans is encoded by the ''MYO15A'' gene. Gene Read-through transcript containing an upstream gene and this gene have been identified, but they are not thought to encode a fusion protein. Several alternatively spliced transcript variants have been described, but their full length sequences have not been determined. Function This gene encodes an unconventional myosin. This protein differs from other myosins in that it has a long N-terminal extension preceding the conserved motor domain. Studies in mice suggest that this protein is necessary for actin organization in the hair cells of the cochlea. Clinical significance Mutations in this gene have been associated with profound, congenital, neurosensory, nonsyndromic deafness. This gene is located within the Smith–Magenis syndrome Smith–Magenis syndrome (SMS), also known as 17p-microdeletion syndrome, is a microdeletion syndrome characterized by an abnormality in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
KCNQ4
Potassium voltage-gated channel subfamily KQT member 4, also known as voltage-gated potassium channel subunit Kv7.4, is a protein that in humans is encoded by the ''KCNQ4'' gene. Function The protein encoded by this gene forms a potassium channel that is thought to play a critical role in the regulation of neuronal excitability, particularly in sensory cells of the cochlea. The encoded protein can form a homomultimeric potassium channel or possibly a heteromultimeric channel in association with the protein encoded by the KCNQ3 gene. Clinical significance The current generated by this channel is inhibited by muscarinic acetylcholine receptor M1 and activated by retigabine, a novel anti-convulsant drug. Defects in this gene are a cause of nonsyndromic sensorineural deafness type 2 (DFNA2), an autosomal dominant form of progressive hearing loss. Two transcript variants encoding different isoforms have been found for this gene. Ligands * ML213: KCNQ2/Q4 channel opener. S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GJB6
Gap junction beta-6 protein (GJB6), also known as connexin 30 (Cx30) — is a protein that in humans is encoded by the ''GJB6'' gene. Connexin 30 (Cx30) is one of several gap junction proteins expressed in the inner ear. Mutations in gap junction genes have been found to lead to both syndromic and nonsyndromic deafness. Mutations in this gene are associated with Clouston syndrome (i.e., hydrotic ectodermal dysplasia). Function The connexin gene family codes for the protein subunits of gap junction channels that mediate direct diffusion of ions and metabolites between the cytoplasm of adjacent cells. Connexins span the plasma membrane 4 times, with amino- and carboxy-terminal regions facing the cytoplasm. Connexin genes are expressed in a cell type-specific manner with overlapping specificity. The gap junction channels have unique properties depending on the type of connexins constituting the channel. upplied by OMIMref name="entrez"/> Connexin 30 is prevalent in the two di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
GJB2
Gap junction beta-2 protein (GJB2), also known as connexin 26 (Cx26) — is a protein that in humans is encoded by the ''GJB2'' gene. Function Gap junctions were first characterized by electron microscopy as regionally specialized structures on plasma membranes of contacting adherent cells. These structures were shown to consist of cell-to-cell channels. Proteins, called connexins, purified from fractions of enriched gap junctions from different tissues differ. The connexins are designated by their molecular mass. Another system of nomenclature divides gap junction proteins into two categories, alpha and beta, according to sequence similarities at the nucleotide and amino acid levels. For example, CX43 ( GJA1) is designated alpha-1 gap junction protein, whereas GJB1 (CX32), and GJB2 (CX26; this protein) are called beta-1 and beta-2 gap junction proteins, respectively. This nomenclature emphasizes that GJB1 and GJB2 are more homologous to each other than either of them is to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
EYA4
Eyes absent homolog 4 is a protein that in humans is encoded by the ''EYA4'' gene. This gene encodes a member of the eyes absent (EYA) subfamily of proteins. The encoded protein may act as a transcriptional activator and be important for continued function of the mature organ of Corti The organ of Corti, or spiral organ, is the receptor organ for hearing and is located in the mammalian cochlea. This highly varied strip of epithelial cells allows for transduction of auditory signals into nerve impulses' action potential. Trans .... Mutations in this gene are associated with postlingual, progressive, autosomal dominant hearing loss at the deafness, autosomal dominant nonsyndromic sensorineural 10 locus. Three transcript variants encoding distinct isoforms have been identified for this gene. References Further reading * * * * * * * * * * * {{gene-6-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Espin (protein)
Espin, also known as autosomal recessive deafness type 36 protein or ectoplasmic specialization protein, is a protein that in humans is encoded by the ''ESPN'' gene. Espin is a microfilament Microfilaments, also called actin filaments, are protein filaments in the cytoplasm of eukaryotic cells that form part of the cytoskeleton. They are primarily composed of polymers of actin, but are modified by and interact with numerous other ... binding protein. Function Espin is a multifunctional actin-bundling protein. It plays a major role in regulating the organization, dimensions, dynamics, and signaling capacities of the actin filament-rich, microvillus-type specializations that mediate sensory transduction in various mechanosensory and chemosensory cells. Clinical significance Mutations in this gene are associated with autosomal recessive neurosensory deafness, autosomal dominant sensorineural deafness without vestibular involvement, and DFNB36. References Further read ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DFNA5
Non-syndromic hearing impairment protein 5 is a protein that in humans is encoded by the ''DFNA5'' gene. Function Hearing impairment is a heterogeneous condition with over 40 loci described. The protein encoded by this gene is expressed in fetal cochlea, however, its function is not known. Nonsyndromic hearing impairment is associated with a mutation in this gene. The observation that DFNA5 is epigenetically inactivated in a large number of cancers of frequent types (gastric, colorectal, and breast) is another important finding and is in line with its apoptosis-inducing properties. Indeed, if apoptosis Apoptosis (from ) is a form of programmed cell death that occurs in multicellular organisms and in some eukaryotic, single-celled microorganisms such as yeast. Biochemistry, Biochemical events lead to characteristic cell changes (Morphology (biol ... is an intrinsic feature of DFNA5, shutting the gene down in tumor cells makes them more susceptible to uncontrolled cellular gr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
