Retinitis pigmentosa

Write-up by jekky

Signs Mottling of the retinal pigment epithelium with black bone-spicule pigmentation is typically indicative (or pathognomonic) of retinitis pigmentosa. Other ocular attributes consist of waxy pallor of the optic nerve head, attenuation (thinning) of the retinal vessels, cellophane maculopathy, cystic macular edema and posterior subcapsular cataract. Diagnosis The diagnosis of retinitis pigmentosa relies upon documentation of progressive loss in photoreceptor function by electroretinography (ERG) and visual field testing. The mode of inheritance of RP is determined by family members history. At least 35 various genes or loci are known to trigger "nonsyndromic RP" (RP that is not the result of an additional illness or component of a wider syndrome). DNA testing is available on a clinical basis for: RLBP1 (autosomal recessive, Bothnia sort RP) RP1 (autosomal dominant, RP1) RHO (autosomal dominant, RP4) RDS (autosomal dominant, RP7) PRPF8 (autosomal dominant, RP13) PRPF3 (autosomal dominant, RP18) CRB1 (autosomal recessive, RP12) ABCA4 (autosomal recessive, RP19) RPE65 (autosomal recessive, RP20) For all other genes, molecular genetic testing is accessible on a study basis only. RP can be inherited in an autosomal dominant, autosomal recessive, or X-linked manner. X-linked RP can be either recessive, affecting primarily only males, or dominant, affecting both males and females, even though males are normally much more mildly affected. Some digenic (controlled by two genes) and mitochondrial forms have also been described. Genetic counseling depends on an accurate diagnosis, determination of the mode of inheritance in each family, and results of molecular genetic testing. Associations Retinitis pigmentosa is observed in a selection of diseases, so the differential of this sign alone, is broad. RP combined with progressive deafness is known as Usher syndrome. RP combined with opthalmoplegia, dysphagia, ataxia, and cardiac conduction defects is observed in the mitochondrial DNA disorder Kearns-Sayre Syndrome (aka Ragged Red Fiber Myopathy) RP combined with retardation, peripheral neuropathy, acanthotic (spiked) RBCs, ataxia, steatorrhea, is absence of VLDL is observed in abetalipoproteinemia. Other conditions consist of neurosyphilis, toxoplasmosis(Emedicine "Retinitis Pigmentosa"), abetalipoproteinemia, and Refsum's disease. Genetics Retinitis pigmentosa (RP) is 1 of the most common forms of inherited retinal degeneration. This disorder is characterized by the progressive loss of photoreceptor cells and might ultimately lead to blindness. There are several genes that, when mutated, can cause the Retinitis pigmentosa phenotype. In 1989, a mutation of the gene for rhodopsin, a pigment that plays an crucial component in the visual transduction cascade enabling vision in low-light conditions, was identified. Considering that then, far more than 100 mutations have been found in this gene, accounting for 15% of all kinds of retinal degeneration. Most of those mutations are missense mutations and inherited mostly in a dominant manner. The rhodopsin gene encodes a principal protein of photoreceptor outer segments. Studies show that mutations in this gene are responsible for approximately 25% of autosomal dominant forms of RP. Mutations in four pre-mRNA splicing elements are known to cause autosomal dominant retinitis pigmentosa. These are PRPF3, PRPF8, PRPF31 and PAP1. These factors are ubiquitously expressed and it is still a puzzle as to why defects in a ubiquitous factor ought to only cause disease in the retina. Up to 150 mutations have been reported to date in the opsin gene connected with the RP considering that the Pro23His mutation in the intradiscal domain of the protein was first reported in 1990. These mutations are found all through the opsin gene and are distributed along the three domains of the protein (the intradiscal, transmembrane, and cytoplasmic domains). One of the primary biochemical causes of RP in the case of rhodopsin mutations is protein misfolding, and molecular chaperones have also been involved in RP. It was discovered that the mutation of codon 23 in the rhodopsin gene, in which proline is changed to histidine, accounts for the largest fraction of rhodopsin mutations in the United States. A number of other studies have reported other mutations which also correlate with the illness. These mutations include Thr58Arg, Pro347Leu, Pro347Ser, as properly as deletion of Ile-255. In 2000, a rare mutation in codon 23 was reported causing autosomal dominant retinitis pigmentosa, in which proline changed to alanine. Nonetheless, this study showed that the retinal dystrophy connected with this mutation was characteristically mild in presentation and course. Furthermore, there was higher preservation in electroretinography amplitudes than the a lot more prevalent Pro23His mutation. The progression of the illness can be decreased by the daily intake of 15000 IU (equivalent to 4.5 mg) of vitamin A palmitate. Recent studies have shown that appropriate vitamin A supplementation can postpone blindness by up to 10 years. Scientists continue to investigate probable treatments. Future treatments might involve retinal transplants, artificial retinal implants, gene therapy, stem cells, nutritional supplements, and/or drug therapies. Scientists at the Osaka Bioscience Institute have identified a protein, named Pikachurin, which they think could lead to a treatment for retinitis pigmentosa. In a study published in the journal Nature, researchers working with mice at the University College London Institutes of Ophthalmology and Child Wellness and Moorfields Eye Hospital, transplanted mouse stem cells which had been at an advanced stage of development, and already programmed to develop into photoreceptors, into mice that had been genetically induced to mimic the human conditions of retinitis pigmentosa and age-related macular degeneration. These photoreceptors developed and created the necessary neural connections to the animal's retinal nerve cells, a key step in the restoration of sight. Previously it was believed that the mature retina has no regenerative capability. This study might in the future lead to using transplants in humans to relieve blindness. Notable folks with RP Willie Brown, former Mayor of San Francisco Gordon Gund, U.S. sports team owner Kevin James, American comedian/actor Jim Knipfel, American novelist, autobiographer, and journalist Amar Latif Scottish entrepreneur, television actor, director and motivational speaker Isaac Lidsky, former child actor and very first blind US Supreme Court clerk Woody Shaw, American jazz musician Amanda Swafford, America's Next Top Model Cycle 3 John Totleben, American illustrator Rigo Tovar, Mexican singer, composer, songwriter Mildred Weisenfeld, founder of the Fight for Sight eye analysis foundation in 1946. Steve Wynn, Las Vegas casino developer See also Cone dystrophy Visual prosthetic List of eye diseases and disorders Progressive retinal atrophy for the condition in dogs References ^ Koenekoop, R.K. (2003). Novel RPGR mutations with distinct retinitis pigmentosa phenotypes in French-Canadian families. American journal of ophthalmology 136(4), pp. 678-68 ^ a b Hartong DT, Berson EL, Dryja TP (November 2006). "Retinitis pigmentosa". Lancet 368 (9549): 1795809. doi:10.1016/S0140-6736(06)69740-7. PMID 17113430. ^ Farrar GJ, Kenna PF, Humphries P (March 2002). "On the genetics of retinitis pigmentosa and on mutation-independent approaches to therapeutic intervention". EMBO J. 21 (5): 85764. doi:10.1093/emboj/21.5.857. PMID 11867514. ^ On the web 'Mendelian Inheritance in Man' (OMIM) RETINITIS PIGMENTOSA RP -268000 ^ a b Berson EL, Rosner B, Sandberg MA, Dryja TP (January 1991). "Ocular findings in patients with autosomal dominant retinitis pigmentosa and a rhodopsin gene defect (Pro-23-His)". Arch. Ophthalmol. 109 (1): 92101. PMID 1987956. ^ Senin II, Bosch L, Ramon E, et al. (October 2006). "Ca2+/recoverin dependent regulation of phosphorylation of the rhodopsin mutant R135L linked with retinitis pigmentosa". Biochem. Biophys. Res. Commun. 349 (1): 34552. doi:10.1016/j.bbrc.2006.08.048. PMID 16934219. ^ Dryja TP, McGee TL, Reichel E, et al. (January 1990). "A point mutation of the rhodopsin gene in one form of retinitis pigmentosa". Nature 343 (6256): 3646. doi:10.1038/343364a0. PMID 2137202. ^ Dryja TP, McGee TL, Hahn LB, et al. (November 1990). "Mutations inside the rhodopsin gene in patients with autosomal dominant retinitis pigmentosa". N. Engl. J. Med. 323 (19): 13027. PMID 2215617. ^ Berson EL, Rosner B, Sandberg MA, Weigel-DiFranco C, Dryja TP (May possibly 1991). "Ocular findings in patients with autosomal dominant retinitis pigmentosa and rhodopsin, proline-347-leucine". Am. J. Ophthalmol. 111 (5): 61423. PMID 2021172. ^ Inglehearn CF, Bashir R, Lester DH, Jay M, Bird AC, Bhattacharya SS (January 1991). "A 3-bp deletion in the rhodopsin gene in a family members with autosomal dominant retinitis pigmentosa". Am. J. Hum. Genet. 48 (1): 2630. PMID 1985460. ^ Oh KT, Weleber RG, Lotery A, Oh DM, Billingslea AM, Stone EM (September 2000). "Description of a new mutation in rhodopsin, Pro23Ala, and comparison with electroretinographic and clinical characteristics of the Pro23His mutation". Arch. Ophthalmol. 118 (9): 126976. PMID 10980774. http://archopht.ama-assn.org/cgi/pmidlookup?view=lengthy&pmid=10980774. ^ Berson EL, Rosner B, Sandberg MA, et al. (1993). "A randomized trial of vitamin A and vitamin E supplementation for retinitis pigmentosa". Arch. Ophthalmol. 111 (6): 76172. PMID 8512476. ^ Berson EL (2007). "Lengthy-term visual prognoses in patients with retinitis pigmentosa: the Ludwig von Sallmann lecture". Exp. Eye Res. 85 (1): 714. doi:10.1016/j.exer.2007.03.001. PMID 17531222. ^ Rush University Medical Center (2005-01-31). "Ophthalmologists Implant Five Patients with Artificial Silicon Retina Microchip To Treat Vision Loss from Retinitis Pigmentosa". Press release. http://www.rush.edu/webapps/MEDREL/servlet/NewsRelease?ID=608. Retrieved 2007-06-16. ^ Sato S, Omori Y, Katoh K, et al. (August 2008). "Pikachurin, a dystroglycan ligand, is essential for photoreceptor ribbon synapse formation". Nat. Neurosci. 11 (8): 923931. doi:10.1038/nn.2160. PMID 18641643. ^ Lightning-Fast Vision Protein Named After Pikachu July 24, 2008 ^ MacLaren, RE RA Pearson, A MacNeil, RH Douglas, TE Salt, M Akimoto, A Swaroop, JC Sowden, RR Ali (2006-11-09). "Retinal repair by transplantation of photoreceptor precursors". Nature 444 (7116): 2037. doi:10.1038/nature05161. PMID 17093405. ^ http://www.newyorker.com/archive/2006/10/23/061023ta_talk_paumgarten External links Media related to retinitis pigmentosa at Wikimedia Commons Listen to this article (info/dl) This audio file was created from a revision dated 2006-02-17, and does not reflect subsequent edits to the write-up. (Audio aid) More spoken articles Scyfix.org Retina Pigmentosa Clinical Trials GeneReview/NCBI/NIH/UW entry on Retinitis Pigmentosa Overview Eye Implants to Fight Progressive Blindness New Hope For Regenerating Damaged Human Retina: Sleeping Stem Cells Successfully Awakened Vision Deficit in Retinitis Pigmentosa Mice Corrected with DNA Nanoparticles Gene Therapy For Retinal Diseases Advances With New Viral And Capsule Mechanisms To Place Genes Directly In Eye Retinal Implants Restore Vision Foresight, a Dubai-based charity fighting to uncover a cure for blindness caused by hereditary eye illness, especially Retinitis Pigmentosa The British Retinitis Pigmentosa Society BBC News - Bionic eye 'blindness cure hope' Retina New Zealand MedlinePlus Encyclopedia Retinitis Pigmentosa A lot more about Retinitis Pigmentosa Not Fade Away 1 man's journey into blindness (Exploratorium) Retinal implants could soon restore lost vision The Boston Retinal Implant Project RPlist, the Retinal Degeneration Mailing List The RP-Pals Mailing List is a discussion group where men and women with Retinitis Pigmentosa gather for friendship & support. Retinitis Pigmentosa on Visually Impaired Forums by Exjake.com Breakthrough by MUHC researcher has key implications for diagnosis, treatment of childhood blindness The Foundation Fighting Blindness Visual Mobility Aids for Patients with Night Blindness (AETMIS 06-09) Retina South Africa Polish discussion forum for Patients with Retinitis Pigmentosa Retina International v d e Eye disease pathology of the eye (H00-H59, 360-379) Adnexa eyelid: inflammation (Stye, Chalazion, Blepharitis) Entropion Ectropion Lagophthalmos Blepharochalasis Ptosis Blepharophimosis Xanthelasma eyelash (Trichiasis, Madarosis) lacrimal system: Dacryoadenitis Epiphora Dacryocystitis Xerophthalmia orbit: Exophthalmos Enophthalmos Orbital cellulitis conjunctiva: Conjunctivitis (Allergic conjunctivitis) Pterygium Pinguecula Subconjunctival hemorrhage Globe Fibrous tunic sclera: Scleritis cornea: Keratitis (Herpetic keratitis, Acanthamoeba keratitis, Fungal keratitis) Corneal ulcer Snow blindness Thygeson's superficial punctate keratopathy Corneal dystrophy (Fuchs', Meesmann) Keratoconus Keratoconjunctivitis sicca Arc eye Keratoconjunctivitis Corneal neovascularization Kayser-Fleischer ring Arcus senilis Band keratopathy Vascular tunic Iris and ciliary body Iritis Uveitis (Intermediate uveitis) Iridocyclitis Hyphema Rubeosis iridis Persistent pupillary membrane Iridodialysis Synechia Choroid Choroideremia Choroiditis (Chorioretinitis) Lens Cataract Aphakia Ectopia lentis Retina Retinitis (Chorioretinitis, Cytomegalovirus retinitis) Retinal detachment Retinoschisis Ocular ischemic syndrome/Central retinal vein occlusion Retinopathy (Bietti's crystalline dystrophy, Coats illness, Diabetic retinopathy, Hypertensive retinopathy, Retinopathy of prematurity) Macular degeneration Retinitis pigmentosa Retinal haemorrhage Central serous retinopathy Macular edema Epiretinal membrane Macular pucker Vitelliform macular dystrophy Leber's congenital amaurosis Birdshot chorioretinopathy Other Glaucoma/Ocular hypertension Floater Leber's hereditary optic neuropathy Red eye Keratomycosis Phthisis bulbi Pathways O

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