PERSPECTIVES Hair-Bundle Links: Genetics as the Gateway to Function

We describe the structure of these links and review evidence showing CDH23 and PCDH15 are components of the tip, kinocilial, and transient-lateral links, that stereocilin (STRC) and protein tyrosine phosphatase (PTPRQ) are associated with top and shaft connectors, respectively, and that USH2A and ADGRV1 are associated with the ankle links. Whereas tip links are required for mechanoelectrical transduction, all link proteins play key roles in the normal development and/or the maintenance of hair bundle structure and function. Recent crystallographic and single-particle analyses of PCDH15 and CDH23 provide insight as to how the structure of tip link may contribute to the elastic element predicted to lie in series with the hair cell's mechanoelectrical transducer channel.
Source: Cold Spring Harbor perspectives in medicine - Category: Research Authors: Tags: Function and Dysfunction of the Cochlea PERSPECTIVES Source Type: research

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A 45-year-old woman with Usher syndrome, associated congenital deafness, progressive blindness due to retinitis pigmentosa, and latent autoimmune diabetes presented to the emergency department with malaise, dizziness, and pelvic pain following removal of an intrauterine device. A posterior vaginal wall mass was found on examination. Laboratory values demonstrated anemia, thrombocytopenia, and an elevated white blood cell count, raising concern for infection and potential onset of diabetic ketoacidosis. This prompted a peripheral blood smear review, which showed 60% monocytic blasts. A subsequent vaginal mass biopsy showed ...
Source: Pathology Case Reviews - Category: Pathology Tags: Case Reviews Source Type: research
Identification of whirlin domains interacting with espin: A study of the mechanism of Usher syndrome type II. Mol Med Rep. 2019 Oct 07;: Authors: Wang L, Wei B, Fu X, Wang Y, Sui Y, Ma J, Gong X, Hao J, Xing S Abstract Usher syndrome is the most common condition of combined blindness and deafness and is classified into three types (USH1‑USH3). USH2 is the most commonly diagnosed of all Usher syndrome cases. There are three identified proteins (usherin, GPR98 and whirlin) that form the USH2 complex. Defects in any of these proteins may cause failure in the formation of the USH2 complex, which is ...
Source: Molecular Medicine Reports - Category: Molecular Biology Tags: Mol Med Rep Source Type: research
Usher syndrome, the most common form of inherited deaf-blindness, is unlike many other forms of syndromic hereditary hearing loss in that the extra aural clinical manifestations are also detrimental to communi...
Source: BMC Medical Genetics - Category: Genetics & Stem Cells Authors: Tags: Research article Source Type: research
ier R Abstract BACKGROUND: In Usher syndrome, deafness is congenital and blindness is acquired. Therefore, the progressive loss of one of the two senses forces individuals with this syndrome to reorganize their everyday tasks and relationships, creating new strategies to communicate, access information, and move within a given space. This reorganization can interfere with the subjects' capacity to build a good quality of life. METHODS: We conducted a scoping review of both peer-reviewed and gray literature, to identify existing evidence of the role of psychosocial determinants on the quality of life of people...
Source: Disability and Rehabilitation - Category: Rehabilitation Authors: Tags: Disabil Rehabil Source Type: research
(Sechenov University) A team of scientists from Sechenov First Moscow State Medical University (MSMU) together with their colleagues from leading scientific centers of Moscow and India described a number of genetic mutations causing Usher syndrome (inherited deaf-blindness). They found previously unstudied unique mutations in investigated DNA regions. The results of the study were published in the Ophthalmic Genetics journal.
Source: EurekAlert! - Medicine and Health - Category: International Medicine & Public Health Source Type: news
ABSTRACT Johnston's organ – the hearing organ of Drosophila – has a very different structure and morphology to that of the hearing organs of vertebrates. Nevertheless, it is becoming clear that vertebrate and invertebrate auditory organs share many physiological, molecular and genetic similarities. Here, we compare the molecular and cellular features of hearing organs in Drosophila with those of vertebrates, and discuss recent evidence concerning the functional conservation of Usher proteins between flies and mammals. Mutations in Usher genes cause Usher syndrome, the leading cause of human deafness and blindne...
Source: DMM Disease Models and Mechanisms - Category: Biomedical Science Authors: Tags: REVIEW Source Type: research
Authors: Wolfrum U, Nagel-Wolfrum K Abstract The human Usher syndrome (USH) is a complex, rare disease manifesting in its most common form of inherited deaf-blindness. Due to the heterogeneous manifestation of the clinical symptoms, three clinical types (USH1-3) are distinguished according to the severity of the disease pattern. For a correct diagnosis, in addition to the auditory tests in early newborn screening, ophthalmological examinations and molecular genetic analysis are important. Ten known USH genes encode proteins, which are from heterogeneous protein families, interact in functional protein networks. In ...
Source: Klinische Monatsblatter fur Augenheilkunde - Category: Opthalmology Tags: Klin Monbl Augenheilkd Source Type: research
Conclusions: Although Myo7a is a causal gene of US type I, this gene works with many other genes and pathways to affect the severity of US. Many of the genes found in the genetic network, pathways, and gene ontology categories of Myo7a are related to either deafness or blindness. Further investigation is needed to examine the specific relationships between these genes, which may assist in the treatment of US. PMID: 29430167 [PubMed - in process]
Source: Molecular Vision - Category: Molecular Biology Tags: Mol Vis Source Type: research
Mutations in the MYO7A gene, encoding the motor protein myosin VIIa, can cause Usher 1B, a deafness/blindness syndrome in humans, and the shaker-1 phenotype, characterized by deafness, head tossing, and circling behavior, in mice. Myosin VIIa is responsible for tension bearing and the transduction mechanism in the stereocilia and for melanosome transport in the retina, in line with the phenotypic outcomes observed in mice. However, the effect of the shaker-1 mutation, a R502P amino acid substitution, on the motor function is unclear. To explore this question, we determined the kinetic properties and the effect on the filop...
Source: Journal of Biological Chemistry - Category: Chemistry Authors: Tags: Enzymology Source Type: research
We report here two new nonsense mutations (pGln12* and pTyr110*) in CIB2 patients displaying nonsyndromic profound hearing loss, with no evidence of vestibular or retinal dysfunction. Also, the generated CIB2−/− mice display an early onset profound deafness and have normal balance and retinal functions. In these mice, the mechanoelectrical transduction currents are totally abolished in the auditory hair cells, whilst they remain unchanged in the vestibular hair cells. The hair bundle morphological abnormalities of CIB2−/− mice, unlike those of mice defective for the other five known USH1 proteins, b...
Source: EMBO Molecular Medicine - Category: Molecular Biology Authors: Tags: Research Article Source Type: research
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