Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0004134 (ataxia)
 15,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Failure to control oxidative stress is closely related to aging and to a diverse range of human diseases. We have reported that protein kinase C gamma (PKCgamma) acts as a primary oxidative stress sensor in the lens. PKCgamma has a Zn-finger C1B stress switch domain, residues 101-150. Mutation, H101Y, in the C1B domain of PKCgamma proteins causes a failure of the PKCgamma oxidative stress response [Lin, D., Takemoto, D.J., 2005. Oxidative activation of protein kinase Cgamma through the C1 domain. Effects on gap junctions. J. Biol. Chem. 280, 13682-13693]. Some human neurodegenerative spinocerebellar ataxia type 14 are caused by mutations in the PKCgamma C1B domain. In the current study we have investigated the effects of these mutations on lens epithelial cell responses to oxidative stress. The results demonstrate that PKCgamma C1B mutants had lower basal enzyme activities and were not activated by H(2)O(2). Furthermore, the PKCgamma mutations caused a failure of endogenous wild type PKCgamma to be activated by H(2)O(2). These PKCgamma mutations abolished the effect of H(2)O(2) on phosphorylation of Cx43 and Cx50 by H(2)O(2) activation of PKCgamma. The cells with PKCgamma C1B mutations had more Cx43 and/or Cx50 gap junction plaques which were not decreased by H(2)O(2). Since open gap junctions could have a bystander effect this could cause apoptosis to occur. H(2)O(2) (100 microM, 3 h) activated a caspase-3 apoptotic pathway in the lens epithelial cells but was more severe in cells expressing PKCgamma mutations. The presence of 18alpha-glycyrrhetinic acid (AGA), an inhibitor of gap junctions, decreased Cx43 and Cx50 protein levels and gap junction plaque number. This reduction in gap junctions by AGA resulted in inhibition of H(2)O(2)-induced apoptosis. Our results demonstrate that there is a dominant negative effect of PKCgamma C1B mutations on endogenous PKCgamma which results in loss of control of gap junctions. Modeled structures suggest that the severity of C1B mutation effects may be related to the extent of loss of C1B structure. Mutations in the C1B domain of PKCgamma result in increased apoptosis in lens epithelial cells. This can be prevented by a gap junction inhibitor. Thus, propagation of apoptosis from cell-to-cell in lens epithelial cells may be through open gap junctions. The control of gap junctions requires PKCgamma.
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PMID:Protein kinase C gamma mutations in the C1B domain cause caspase-3-linked apoptosis in lens epithelial cells through gap junctions. 1749 14

The predominantly autosomal dominant disorder, oculodentodigital dysplasia (ODDD) has high penetrance with intra- and interfamilial phenotypic variability. Abnormalities observed in ODDD affect the eye, dentition, and digits of the hands and feet. Patients present with a characteristic facial appearance, narrow nose, and hypoplastic alae nasi. Neurological problems, including dysarthria, neurogenic bladder disturbances, spastic paraparesis, ataxia, anterior tibial muscle weakness, and seizures, are known to occur as well as conductive hearing loss, cardiac defects, and anomalies of the skin, hair, and nails. In 2003, our analysis of 17 ODDD families revealed that each had a different mutation within the human gap junction alpha 1 (GJA1) gene which encodes the protein connexin 43 (Cx43). Since then at least 17 publications have identified an additional 26 GJA1 mutations and in this study, we present 28 new cases with 18 novel GJA1 mutations. We include tables summarizing the 62 known GJA1 nucleotide changes leading to Cx43 protein alterations and the phenotypic information available on 177 affected individuals from 54 genotyped families. Mutations resulting in ODDD occur in each of the nine domains of the Cx43 protein, and we review our functional experiments and those in the literature, examining the effects of 13 different Cx43 mutations upon gap junction activity.
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PMID:GJA1 mutations, variants, and connexin 43 dysfunction as it relates to the oculodentodigital dysplasia phenotype. 1933 53

The coordination of tissue function is mediated by gap junctions (GJs) that enable direct cell-cell transfer of metabolic and electric signals. GJs are formed by connexins of which Cx43 is most widespread in the human body. In the brain, Cx43 GJs are mostly found in astroglia where they coordinate the propagation of Ca(2+) waves, spatial K(+) buffering, and distribution of glucose. Beyond its role in direct intercellular communication, Cx43 also forms unapposed, non-junctional hemichannels in the plasma membrane of glial cells. These allow the passage of several neuro- and gliotransmitters that may, combined with downstream paracrine signaling, complement direct GJ communication among glial cells and sustain glial-neuronal signaling. Mutations in the GJA1 gene encoding Cx43 have been identified in a rare, mostly autosomal dominant syndrome called oculodentodigital dysplasia (ODDD). ODDD patients display a pleiotropic phenotype reflected by eye, hand, teeth, and foot abnormalities, as well as craniofacial and bone malformations. Remarkably, neurological symptoms such as dysarthria, neurogenic bladder (manifested as urinary incontinence), spasticity or muscle weakness, ataxia, and epilepsy are other prominent features observed in ODDD patients. Over 10 mutations detected in patients diagnosed with neurological disorders are associated with altered functionality of Cx43 GJs/hemichannels, but the link between ODDD-related abnormal channel activities and neurologic phenotype is still elusive. Here, we present an overview on the nature of the mutants conveying structural and functional changes of Cx43 channels and discuss available evidence for aberrant Cx43 GJ and hemichannel function. In a final step, we examine the possibilities of how channel dysfunction may lead to some of the neurological manifestations of ODDD.
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PMID:Neurological manifestations of oculodentodigital dysplasia: a Cx43 channelopathy of the central nervous system? 2413 47

Several syndromes have been recognized with digital abnormality and CNS involvement such as oculodentodigital dysplasia (ODDD), Mohr syndrome and Joubert syndrome. We report a patient who was referred to us because of the neurological signs suspicious of metabolic disorders. This case was a 22-year-old woman whose problems began 4 years ago with shortening of memory, ataxia, abnormal gait and diplopia which progressed slowly. She consulted many neurologists and was on treatment with the suspicion of vasculitis, but no response was detected. She had severe short stature, hypoplasia of the middle and distal phalanges of the first, second and third fingers, clinodactyly, abnormal toes, abnormal enamel and missing teeth. She had no characteristic faces of ODDD and ophthalmological abnormality. Our patient might be a variant of ODDD or a new syndrome with somatic and neurologic signs.
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PMID:Digital and dental malformation and short stature in a patient with neurological problems: a variant of the oculodentodigital dysplasia syndrome or a new syndrome? 2466 81

Premature tooth loss is a disastrous situation that affects deciduous or permanent teeth era with different causes. It may be attributed to some disorders like Papillon-Lefevre syndrome or coffin-lowry syndrome but because of ambiguous nature, precise diagnosis is not easily possible. Moreover, it has very low incidence and defines by few and limited case series, with vague characters to some extent, confusion in detecting the right diagnosis is a common possibility. Hence, it is expectable to have a wrong diagnosis for this case. In this study, a 5-yr-old boy with chief complaint of early tooth loss despite having blindness in left eye and palmar keratosis is reported, although he had some other manifestation of oculodentodigital dysplasia (ODDD) like ataxia, dysarthria and nail deformity, ignoring other extra and intra oral finding. He was diagnosed as Papillon-Lefevre syndrome already, just because of early tooth loss and palmar keratosis.
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PMID:A Highlighted Case for Emphasizing on Clinical Diagnosis for Rare Syndrome in Third World. 2920 Nov 28