Oculopharyngeal muscular dystrophy
Oculopharyngeal muscular dystrophy (OPMD) is an autosomal dominant[1] neuromuscular disease which appears in early middle age (sixth decade).[2] OPMD is an example of a trinucleotide repeat disorder caused by expanding (GCN)10 to (GCN)11-17 at the 5' end of the coding region for PABPN1. This expands the polyalanine tract at the N-terminus of PABPN1 from 10 to 11-17 alanines.[3][4]
Signs and symptoms
Progressive ptosis (drooping of eyelids)and weakness of the extraocular muscles is the initial clinical finding which continues until paralysis of all eye movements occurs; however, pupillary reactions remain unaffected. Dysphagia (difficulty swallowing), facial weakness and proximal limb weakness develops later on in the disease. [2]
Diagnosis
A muscle biopsy reveals abnormal vacuoles within muscle fibres. A distinction between OPMD and myasthenia gravis or mitochondrial myopathy must be made. The absence of family history and the fluctuation of symptoms in myasthenia gravis usually distinguish the two conditions.[5]
Epidemiology
The disease is frequently seen in French Canadians, with a prevalence 1:1000. A 1997 study from Israel showed the second largest cluster of known individuals are of Bukhara Jews from Uzbekistan, with a calculated minimal prevalence of 1:600. [6] The disease is uncommon in Asian populations. [7]
Treatment
Treatment is supportive to the patient with death eventually occurring from infections. Difficulty with swallowing may result in nasogastric feeding.[3] Some surgeries are available that can reduce ptosis and dysphagia.[8]
References
- ^ Davies Je, B. Z. (February 2006). "Oculopharyngeal muscular dystrophy: Potential therapies for an aggregate-associated disorder". The International Journal of Biochemistry & Cell Biology 38 (9): 1457–1462. doi:10.1016/j.biocel.2006.01.016. PMID 16530457. edit
- ^ a b Brais B, Bouchard JP, Xie YG, et al. (Feb 1998). "Short GCG expansions in the PABP2 gene cause oculopharyngeal muscular dystrophy". Nat. Genet. 18 (2): 164–7. doi:10.1038/ng0298-164. PMID 9462747.
- ^ a b Lindsay, Kenneth W; Ian Bone, Robin Callander, J. van Gijn (1991). Neurology and Neurosurgery Illustrated. United States: Churchill Livingstone. pp. 453. ISBN 0-443-04345-0.
- ^ Goh KJ, Wong KT, Nishino I, Minami N, Nonaka I (2005). "Oculopharyngeal muscular dystrophy with PABPN1 mutation in a Chinese Malaysian woman". Neuromuscul. Disord. 15 (3): 262–4. doi:10.1016/j.nmd.2004.10.016. PMID 15725589. http://linkinghub.elsevier.com/retrieve/pii/S0960-8966(04)00308-6.
- ^ http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=gene&part=opmd
- ^ http://www.ncbi.nlm.nih.gov/pubmed/9392014
- ^ http://memo.cgu.edu.tw/cgmj/3301/330105.pdf
- ^ Brais, B (2009 Jan). "Oculopharyngeal muscular dystrophy: a polyalanine myopathy.". Current neurology and neuroscience reports 9 (1): 76–82. PMID 19080757.
External links
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| The Nine Primary Muscular Dystrophies |
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Related topics
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anat (h/n, u, t/d, a/p, l)/phys/devp/hist
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noco(m, s, c)/cong(d)/tumr, sysi/epon, injr
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Disorders of transcription and post transcriptional modification
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| Chromatin remodeling |
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| Polyadenylation |
PABPN1 (Oculopharyngeal muscular dystrophy)
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| RNA splicing |
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see also transcription, post transcriptional modification
B structural (perx, skel, cili, mito, nucl, sclr) · DNA/RNA/protein synthesis (drep, trfc, tscr, tltn) · membrane (icha, slcr, atpa, abct, othr) · transduction (iter, csrc, itra), trfk
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