Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029089 (ophthalmoplegia)
 3,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Autosomal dominant optic atrophy (ADOA) is the most common form of inherited optic atrophy. Four genetic loci have been associated with ADOA: OPA1, OPA2, OPA3, and OPA4. Out of these four loci, only one gene has been identified, OPA1. We previously described a unique syndrome of optic atrophy, sensorineural hearing loss, ptosis, and ophthalmoplegia in two unrelated families associated with an R445H mutation in OPA1. The R445H mutation is the only OPA1 mutation that has been associated with this syndrome. In this manuscript, we clinically characterize an unrelated family with four members affected by optic atrophy and hearing loss without extraocular motility abnormalities or ptosis. This family also harbors the R445H mutation. These cases help illustrate the intra- and inter-family variability in phenotype associated with this mutation. As we continue to learn more about OPA1 and the function of its protein product, we will begin to understand the pathophysiology of optic atrophy. This understanding will ultimately lead to novel treatments directed toward preventing the visual loss and disability associated with this inherited disease.
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PMID:Optic atrophy and sensorineural hearing loss in a family caused by an R445H OPA1 mutation. 1615 27

Mutations in nuclear genes involved in mitochondrial DNA (mtDNA) maintenance cause a wide range of clinical phenotypes associated with the secondary accumulation of multiple mtDNA deletions in affected tissues. The majority of families with autosomal dominant progressive external ophthalmoplegia (PEO) harbour mutations in genes encoding one of three well-characterized proteins--pol gamma, Twinkle or Ant 1. Here we show that a heterozygous mis-sense mutation in OPA1 leads to multiple mtDNA deletions in skeletal muscle and a mosaic defect of cytochrome c oxidase (COX). The disorder presented with visual failure and optic atrophy in childhood, followed by PEO, ataxia, deafness and a sensory-motor neuropathy in adult life. COX-deficient skeletal muscle fibres contained supra-threshold levels of multiple mtDNA deletions, and genetic linkage, sequencing and expression analysis excluded POLG1, PEO1 and SLC25A4, the gene encoding Ant 1, as the cause. This demonstrates the importance of OPA1 in mtDNA maintenance, and implicates OPA1 in diseases associated with secondary defects of mtDNA.
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PMID:Mutation of OPA1 causes dominant optic atrophy with external ophthalmoplegia, ataxia, deafness and multiple mitochondrial DNA deletions: a novel disorder of mtDNA maintenance. 1822 90

Mutations in OPA1, a dynamin-related GTPase involved in mitochondrial fusion, cristae organization and control of apoptosis, have been linked to non-syndromic optic neuropathy transmitted as an autosomal-dominant trait (DOA). We here report on eight patients from six independent families showing that mutations in the OPA1 gene can also be responsible for a syndromic form of DOA associated with sensorineural deafness, ataxia, axonal sensory-motor polyneuropathy, chronic progressive external ophthalmoplegia and mitochondrial myopathy with cytochrome c oxidase negative and Ragged Red Fibres. Most remarkably, we demonstrate that these patients all harboured multiple deletions of mitochondrial DNA (mtDNA) in their skeletal muscle, thus revealing an unrecognized role of the OPA1 protein in mtDNA stability. The five OPA1 mutations associated with these DOA 'plus' phenotypes were all mis-sense point mutations affecting highly conserved amino acid positions and the nuclear genes previously known to induce mtDNA multiple deletions such as POLG1, PEO1 (Twinkle) and SLC25A4 (ANT1) were ruled out. Our results show that certain OPA1 mutations exert a dominant negative effect responsible for multi-systemic disease, closely related to classical mitochondrial cytopathies, by a mechanism involving mtDNA instability.
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PMID:OPA1 mutations induce mitochondrial DNA instability and optic atrophy 'plus' phenotypes. 1822 90

Multiple deletions of mitochondrial DNA (mtDNA) are associated with different mitochondrial disorders inherited as autosomal dominant and recessive traits. Causative mutations have been found in five genes, mainly involved in mtDNA replication and stability. They include POLG1, the gene encoding the catalytic subunit of mtDNA polymerase (pol gamma), POLG2 encoding its accessory subunit, ANT1 coding the adenine nucleotide translocator and PEO1 which codes for Twinkle, the mitochondrial helicase. Finally OPA1 missense mutations are involved in phenotypes presenting optic atrophy as a major feature.To define the relative contribution of POLG1, POLG2, ANT1 and PEO1 genes to the mtDNA multiple deletion syndromes, we analysed them in a cohort of 67 probands showing accumulation of multiple mtDNA deletions in muscle. The patients were predominantly affected with a mitochondrial myopathy with or without progressive external ophthalmoplegia (PEO). Genetic analysis revealed that 1) PEO1 has a major role in determining familial PEO, since it accounts for 26.8% of familial cases, followed by ANT1 (14.6%) and POLG1 (9.8%); 2) no mutations in any of the known genes were found in 53.7% of probands of this series. Six novel missense mutations contributing to the mutational load of PEO1 gene (p.R334P, p.W315S, p. S426N, p.W474S, p.F478I, p.E479K) were associated with an adult onset PEO phenotype.
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PMID:Novel Twinkle (PEO1) gene mutations in mendelian progressive external ophthalmoplegia. 1857 22

Autosomal-dominant progressive external ophthalmoplegia (adPEO) is a mitochondrial disorder that is characterized by accumulation of multiple mitochondrial DNA (mtDNA) deletions in postmitotic tissues. The disorder is heterogeneous, with five known nuclear disease genes that encode the proteins ANT1, Twinkle, POLG, POLG2, and OPA1. Defects in these proteins affect mtDNA maintenance, probably leading to stalled replication forks, consequent mtDNA deletion formation, and progressive respiratory chain deficiency. Here we present a large adPEO family with multiple mtDNA deletions, whose disease was not explained by mutations in any of the known adPEO loci. We mapped the disease locus in this family to chromosome 8q22.1-q23.3. The critical linkage region contained the RRM2B gene, which encodes the small subunit of the ribonucleotide reductase p53R2, which has previously been shown to be essential for the maintenance of mtDNA copy number. Mutation screening of RRM2B revealed a heterozygous nonsense mutation in exon 9 (c.979C-->T [p.R327X]) in all affected individuals that was absent in 380 control chromosomes. The same mutation was found to segregate in another adPEO family. The mutant mRNA escaped nonsense-mediated decay and resulted in a protein with truncation of 25 highly conserved C-terminal amino acids essential for the interaction with the ribonucleotide reductase subunit R1. We conclude that dominant-negative or gain-of-function mutations in RRM2B are a cause of multiple mtDNA deletions and adPEO.
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PMID:A heterozygous truncating mutation in RRM2B causes autosomal-dominant progressive external ophthalmoplegia with multiple mtDNA deletions. 1966 47

Autosomal dominant Progressive External Ophthalmoplegias are Mendelian disorders characterized by the accumulation of multiple deletions of mitochondrial DNA in critical tissues. Most of the Autosomal dominant Progressive External Ophthalmoplegias families carry heterozygous mutations in one of three genes: ANT1, encoding the muscle-heart specific mitochondrial adenine nucleotide translocator, Twinkle, encoding the mitochondrial DNA helicase, and POLG1, encoding the catalytic subunit of the mitochondrial DNA-specific polymerase. Mutations in both POLG1 alleles are also found in autosomal recessive Progressive External Ophthalmoplegias sibships with multiple affected members and in apparently sporadic cases. In addition, recessive POLG1 mutations are responsible for three additional diseases: Alpers-Huttenlocher hepatopathic poliodystrophy, Sensory-Ataxic Neuropathy Dysarthria and Ophthalmoplegia and juvenile SpinoCerebellar Ataxia-Epilepsy syndrome. Mitochondrial neuro-gastro-intestinal encephalomyopathy is an autosomal recessive disorder of juvenile onset, caused by mutations in the gene encoding Thymidine Phosphorylase. Thymidine Phosphorylase is involved in the control and maintenance of the pyrimidine nucleoside pool of the cell. Finally, mitochondrial DNA depletion syndrome is a heterogeneous group of disorders characterized by a reduction in mitochondrial DNA copy number. Clinically, they include a myopathic form, a more generalized encephalomyopathic form and a fatal infantile hepato-cerebral syndrome leading to rapidly progressive liver and brain failure. To date, eight genes have been associated with mitochondrial DNA depletion syndrome. Novel disease genes have recently been added to this list, including OPA1 and GFER, and new clinical variants add further complexity to this expanding area of mitochondrial medicine.
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PMID:Encephalomyopathies caused by abnormal nuclear-mitochondrial intergenomic cross-talk. 1977 89

Additional neurological features have recently been described in seven families transmitting pathogenic mutations in OPA1, the most common cause of autosomal dominant optic atrophy. However, the frequency of these syndromal 'dominant optic atrophy plus' variants and the extent of neurological involvement have not been established. In this large multi-centre study of 104 patients from 45 independent families, including 60 new cases, we show that extra-ocular neurological complications are common in OPA1 disease, and affect up to 20% of all mutational carriers. Bilateral sensorineural deafness beginning in late childhood and early adulthood was a prominent manifestation, followed by a combination of ataxia, myopathy, peripheral neuropathy and progressive external ophthalmoplegia from the third decade of life onwards. We also identified novel clinical presentations with spastic paraparesis mimicking hereditary spastic paraplegia, and a multiple sclerosis-like illness. In contrast to initial reports, multi-system neurological disease was associated with all mutational subtypes, although there was an increased risk with missense mutations [odds ratio = 3.06, 95% confidence interval = 1.44-6.49; P = 0.0027], and mutations located within the guanosine triphosphate-ase region (odds ratio = 2.29, 95% confidence interval = 1.08-4.82; P = 0.0271). Histochemical and molecular characterization of skeletal muscle biopsies revealed the presence of cytochrome c oxidase-deficient fibres and multiple mitochondrial DNA deletions in the majority of patients harbouring OPA1 mutations, even in those with isolated optic nerve involvement. However, the cytochrome c oxidase-deficient load was over four times higher in the dominant optic atrophy + group compared to the pure optic neuropathy group, implicating a causal role for these secondary mitochondrial DNA defects in disease pathophysiology. Individuals with dominant optic atrophy plus phenotypes also had significantly worse visual outcomes, and careful surveillance is therefore mandatory to optimize the detection and management of neurological disability in a group of patients who already have significant visual impairment.
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PMID:Multi-system neurological disease is common in patients with OPA1 mutations. 2514 16

Autosomal dominant optic nerve atrophy is the most frequent dominantly inherited optic neuropathy. The main causesof the disease are OPA1 gene mutations, which are detected in about 60% of patients. Encoded by the nuclear genome the OPA1 protein plays an important role in a wide variety of processes crucial to the proper functioning of mitochondria, the role of OPAl in many of them has been discovered recently. A detailed study of patients with mutations in the OPA1 gene has shown that about 20% of them present symptoms of a multiple system disease, which may include hearing loss, progressive external ophthalmoplegia, ataxia, myopathy, peripheral neuropathy, spastic paraparesis and multiple sclerosis-like illness. This clinical manifestation is difficult to differentiate from other neurodegenerative diseases, that is why genetic testing is very important in order to determine the molecular basis of the disease in these patients.
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PMID:[Not only optic neuropathy: new molecular and clinical aspects of OPA1 gene mutations]. 2513 24

Pathogenic mutations in the OPA1 gene can be associated with Autosomal Dominant Optic Atrophy (ADOA). In approximately 20 % of patients with OPA1 mutations, a more complex neurodegenerative disorder with extraocular manifestations, known as ADOA Plus, can arise. 12 members of a multigenerational family were assessed clinically and screened for a genetic mutation in OPA1. Eight family members displayed manifestations consistent with ADOA Plus and four did not. Affected members of the oldest available generation displayed the most severe phenotype, which included severe optic atrophy, deafness, ptosis, ophthalmoplegia, proximal myopathy, neuropathy and ataxia. The next generation was less severely affected but several members displayed manifestations only after the fifth decade. Genetic analysis revealed a heterozygous variant in the OPA1 gene (c.1053T>A, p.Asp351Glu) that segregated with disease. The affected family members described here exhibited visual loss later than is typical for OPA1-related disease, as well as later onset of other neurological abnormalities in the fifth or sixth decades of life that progressed to severe neurological disability by the seventh decade. These findings expand the clinical spectrum of OPA1-related disease associated with a novel OPA1 mutation.
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PMID:A novel OPA1 mutation causing variable age of onset autosomal dominant optic atrophy plus in an Australian family. 2619 96

The prevalence of congenital ocular malformations has been described to vary from 0.04 to 6.8 per 10,000 live births. The nuclear mutations identified in chronic progressive external ophthalmoplegia harbor multiple mtDNA deletions that include POLG mutations, PEO1 mutations, OPA1 mutations and RRM2B mutations. In Kearns-Sayre syndrome, the spontaneous mitochondrial deletions vary from 1.3 to 8.0 kb subunits of the oxidative phosphorylation enzymes and several t-RNA genes are affected. Oculopharyngeal muscle dystrophy is both autosomal dominant and recessive form. Congenital fibrosis of extraocular muscles (CFEOM) 1 has mutations in KIF21A on chromosome 12 with TUBB3 mutation also being seen. CFEOM 2 is an autosomal recessive, genetically distinct entity with homozygous mutations in PHOX2A. CFEOM 3 is autosomal dominant heterozygous missense mutations in TUBB3. Most cases of Mobius syndrome are sporadic with familial cases being autosomal dominant, autosomal recessive or X-linked recessive inheritance. Genetic testing has shown abnormalities involving chromosome 1 and 13. Presynaptic congenital myasthenic syndrome is caused by ChAT (choline acetyltransferase) mutation. Two loci have been found for myotonic dystrophy (DM). DM1, which is associated with trinucleotide expansion on chromosome 19q13.3 and DM2 which is associated with CCTG tetranucleotide expansion at 3q21. Blepharophimosis is caused by mutations in the FOXL2 gene 49 located at chromosome 3q23. Lymphedema-distichiasis is an autosomal dominant disorder caused by mutations in the FOXC2 gene.
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PMID:Genetics of strabismus and lid diseases. 2762 84


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