NationMaster - Encyclopedia: Retinitis pigmentosa

Retinitis pigmentosa, or RP, is a group of genetic eye conditions. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades. Many people with RP do not become legally blind until their 40s or 50s and retain some sight all their life. Others go completely blind from RP, in some cases as early as childhood. Progression of RP is different in each case. The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The International Statistical Classification of Diseases and Related Health Problems 10th Revision (ICD-10) is a coding of diseases and signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or diseases, as classified by the World Health Organization (WHO). ... // H00-H59 - Diseases of the eye and adnexa (H00-H06) Disorders of eyelid, lacrimal system and orbit (H00) Hordeolum and chalazion (H000) Hordeolum and other deep inflammation of eyelid (H001) Chalazion (H01) Other inflammation of eyelid (H010) Blepharitis (H011) Noninfectious dermatoses of eyelid (H02) Other disorders of eyelid (H020) Entropion... The International Statistical Classification of Diseases and Related Health Problems (most commonly known by the abbreviation ICD) provides codes to classify diseases and a wide variety of signs, symptoms, abnormal findings, complaints, social circumstances and external causes of injury or disease. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ... Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... human eyesight two children and ball normal vision Copyright: public domain, US gov. ... human eyesight two children and ball normal vision Copyright: public domain, US gov. ... The National Institutes of Health (NIH) is the primary agency of the United States government responsible for medical research. ... The National Eye Institute (NEI) is one of the US National Institutes of Health that was established in 1968. ... human eyesight two children and ball with retinitis pigmentosa or tunnel vision Copyright: public domain, US gov. ... human eyesight two children and ball with retinitis pigmentosa or tunnel vision Copyright: public domain, US gov. ... A human eye Eyes are organs of vision that detect light. ... Nyctalopia (Greek for night blindness) is a condition making it difficult or impossible to see in relatively low light. ... It has been suggested that this article or section be merged with Bitemporal hemianopia. ... Blindness is the condition of lacking visual perception due to physiological or psychological factors. ...

RP is a group of inherited disorders in which abnormalities of the photoreceptors (rods and cones) or the retinal pigment epithelium (RPE) of the retina lead to progressive visual loss. Affected individuals first experience defective dark adaptation or nyctalopia (night blindness), followed by constriction of the peripheral visual field and, eventually, loss of central vision late in the course of the disease. Photoreceptors are light-sensitive proteins involved in the function of photoreceptor cells. ... Rod cells, or rods, are photoreceptor cells in the retina of the eye that can function in less intense light than can the other type of photoreceptor, cone cells. ... Normalised absorption spectra of human cone (S,M,L) and rod (R) cells Cone cells, or cones, are cells in the retina of the eye which only function in relatively bright light. ... Human eye cross-sectional view. ... Nyctalopia (Greek for night blindness) is a condition making it difficult or impossible to see in relatively low light. ... Peripheral vision is a part of vision that occurs outside the very center of gaze. ...

Signs

Mottling of the retinal pigment epithelium with bone-spicule pigmentation is typically pathognomonic for retinitis pigmentosa. Other ocular features include waxy pallor of the optic nerve head, attenuated 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 history. At least 35 different genes or loci are known to cause nonsyndromic RP. DNA testing is available on a clinical basis for RLBP1 (autosomal recessive, Bothnia type 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), and RPE65 (autosomal recessive, RP20). For all other genes, molecular genetic testing is available on a research basis only. Electroretinography, is used to measure the electrical responses of various cell types in the retina, including the light-sensitive cells (rods and cones) and the ganglion cells. ... Genetic testing allows the genetic diagnosis of vulnerabilities to inherited diseases, and can also be used to determine a persons ancestry. ...

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, although females are usually more mildly affected. Some digenic 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. RP combined with progressive deafness is called Usher syndrome. It has been suggested that this article or section be merged into Dominance relationship. ... In genetics, the term recessive gene refers to an allele that causes a phenotype (visible or detectable characteristic) that is only seen in a homozygous genotype (an organism that has two copies of the same allele). ... It has been suggested that sex chromosome be merged into this article or section. ... Genetic counseling is the process by which patients or relatives, at risk of an inherited disorder, are advised of the consequences and nature of the disorder, the probability of developing or transmitting it, and the options open to them in management and family planning in order to prevent, avoid or... Usher syndrome is a genetic disease causing deaf-blindness. ...

Genetics

In 1989, a mutation of the gene for rhodopsin, a pigment that plays an essential part in the visual transduction cascade, was identified. Since then, more than 100 mutations have been found in this gene, accounting for 15% of all types of retinal degeneration. Most of those mutations are missense mutation and inherited mostly in a dominant manner. A rhodopsin molecule (yellow) with bound retinal (orange), embedded in a cell membrane (lipids shown as green, head groups as red/blue). ...

There are multiple genes that, when mutated, can cause the Retinitis pigmentosa phenotype. For more information, see Mendelian Inheritance in Man (OMIM) 268000 The Mendelian Inheritance in Man project is a database that catalogues all the known diseases with a genetic component, and - when possible - links them to the relevant genes in the human genome. ...

Treatment

There is currently no medical treatment for retinitis pigmentosa, although scientists continue to investigate possible treatments. Future treatments may involve retinal transplants, artificial retinal implants,^[1] gene therapy, stem cells, nutritional supplements, and/or drug therapies. Gene therapy is the insertion of genes into an individuals cells and tissues to treat a disease, and hereditary diseases in which a defective mutant allele is replaced with a functional one. ... Mouse embryonic stem cells with fluorescent marker. ... A dietary supplement is intended to supply nutrients, (vitamins, minerals, fatty acids or amino acids) that are missing or not consumed in sufficient quantity in a persons diet. ... Pharmacology (in Greek: pharmakos (Ï†Î¬ÏÎ¼Î±ÎºÎ¿Î½) meaning drug, and logos (Î»ÏŒÎ³Î¿Ï‚) meaning science) is the study of how substances interact with living organisms to produce a change in function. ...

In a study published in the journal Nature, researchers working with mice at the University College London Institutes of Ophthalmology and Child Health and Moorfields Eye Hospital, transplanted mouse stem cells which were 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 made 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 ability. This research may in the future lead to using transplants in humans to relieve blindness.^[2] Nature is one of the most prominent scientific journals, first published on 4 November 1869. ... University College London, commonly known as UCL, is a college of the University of London. ... Moorfields Eye Hospital. ... Listen to this article Â· (info) Â· play in browser This audio file was created from an article revision dated 2005-07-19, and may not reflect subsequent edits to the article. ...

See also

This article lacks information on the importance of the subject matter. ... This is a partial list of human eye diseases and disorders. ... Progressive retinal atrophy (PRA) is a genetic disease of the retina that occurs bilaterally and is seen in certain breeds of dogs. ...

References

Rush University is a private university in Chicago, Illinois. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... is the 31st day of the year in the Gregorian calendar. ... A news release, press release or press statement is a written or recorded communication directed at members of the news media for the purpose of announcing something claimed as having news value. ... Year 2007 (MMVII) is now the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 167th day of the year (168th in leap years) in the Gregorian calendar. ... For the Manfred Mann album, see 2006 (album). ... is the 313th day of the year (314th in leap years) in the Gregorian calendar. ... Galunggung in 1982, showing a combination of natural events. ...

Bibliography

External links

Categories: Spoken articles | Genetic disorders | Ophthalmology | Channelopathy | Blindness Refraction error, also known as refractive error, is an error in the focusing of light by the eye and a frequent reason for reduced visual acuity. ... Hyperopia, also known as hypermetropia or colloquially as farsightedness or longsightedness, is a defect of vision caused by an imperfection in the eye (often when the eyeball is too short or when the lens cannot become round enough), causing inability to focus on near objects, and in extreme cases causing... Normal vision. ... Astigmatism is an affliction of the eye, where vision is blurred by an irregularly shaped cornea. ... Anisometropia is a condition in which the lenses of the two eyes have different focal lengths; that is, are in different states of myopia (nearsightedness) and hyperopia (farsightedness). ... Aniseikonia is an ophthalmological condition caused by unequal retinal image sizes. ... Presbyopia (Greek word presbyteros (Ï€ÏÎµÏƒÎ²ÏÏ„ÎµÏÎ¿Ï‚), meaning elder) is the eyes diminished ability to focus that occurs with aging. ... Blindness is the condition of lacking visual perception due to physiological or psychological factors. ... Amblyopia, or lazy eye, is a disorder of the eye. ... Lebers congenital amaurosis is a rare inherited eye disease that appears at birth or in the first few months of life, typically characterized by nystagmus, sluggish or no pupillary responses, and severe vision loss or blindness. ... Asthenopia is an ophthalmological condition that manifests itself through nonspecific symptoms such as fatigue, red eyes, eye strain, pain in or around the eyes, blurred vision, headache and occasional double vision. ... Hemeralopia is the exact opposite of Nyctalopia (Night Blindness). ... Photophobia (also light sensitivity) or fear of light, is a symptom of excessive sensitivity to light and the aversion to sunlight or well-lit places. ... Scintillating scotoma is the most common visual aura preceding migraine and was first described by 19th century physician Hubert Airy (1838â€“1903). ... Diplopia, commonly known as double vision, is the perception of two images from a single object. ... The word scotoma is derived from the Greek word for darkness. ... An anopsia (or anopia) is a defect in the visual field. ... Binasal hemianopsia is the medical description of a type of partial blindness that is associated with certain lesions of the eye, and of the central nervous system, such as congenital hydrocephlus. ... Paris as seen with full visual fields Paris as seen with bitemporal hemianopsia Bitemporal hemianopsia is the medical description of a type of partial blindness that is associated with lesions of the optic chiasm, the area where the optic nerves from the right and left eyes cross near the pituitary... Homonymous hemianopsia is a medical term for a type of partial blindness resulting in a loss of vision in the same visual field of both eyes. ... Quadrantanopia (or quadrant anopia, as two words) refers to an anopia affecting a quarter of the field of vision. ... Color blindness in humans is the inability to perceive differences between some or all colors that other people can distinguish. ... Achromatopsia is the inability to see color. ... Nyctalopia (Greek for night blindness) is a condition making it difficult or impossible to see in relatively low light. ... Blindness is the condition of lacking visual perception due to physiological or psychological factors. ... Low vision is alternatively a general term used to describe lowered visual acuity, and a specific legal term in Canada and the United States used to designate someone with vision of 20/70 or less in the better eye with correction. ... The human eye The pupil is the central transparent area (showing as black). ... Anisocoria is a condition characterized by an unequal size of the pupils. ... Argyll Robertson pupils (â€œAR pupilsâ€) are bilateral small pupils that constrict when the patient focuses on a near object (they â€œaccommodateâ€ with near vision), but do not constrict when exposed to bright light (they do not â€œreactâ€ to light). ... The pupil dilates instead of constricting when the light moves from the good eye to the bad eye. ... Marcus Gunn Phenomenon (a. ... Adie syndrome, also Adies syndrome, is caused by damage to the postganglionic fibers of the parasympathetic innervation of the eye and characterized by a tonically dilated pupil. ... Infection is also the title of an episode of the television series Babylon 5; see Infection (Babylon 5). ... Binomial name Onchocerca volvulus Bickel 1982 Onchocerciasis (pronounced ) or river blindness is the worlds second leading infectious cause of blindness. ... Nystagmus is involuntary eye movement that can be part of the vestibulo-ocular reflex (VOR), with the eyes moving first in the direction of the lesioned side (slow phase) followed by a quick correction (fast phase) to the opposite side or away from the lesioned side. ... // Mydriasis is an excessive dilation of the pupil due to disease or drugs. ... For other uses, see Floater (disambiguation). ... Leberâ€™s hereditary optic neuropathy (LHON) or Leber optic atrophy is a mitochondrially inherited (mother to all offspring) form of acute or subacute loss of central vision that may lead to degeneration of retinal ganglion cells (RGCs) and their axons; this affects predominantly young adult males. ... Many primary care physicians often deal with patients with red eyes In medicine, red eye is a non-specific term to describe an eye that appears red due to illness, injury, or some other condition. ... A fungal keratitis is an inflammation of the eyes cornea (called keratitis) that results from infection by a fungal organism. ... Xerophthalmia (Greek for dry eyes) is a medical condition in which the eye doesnt produce tears. ... Aniridia is a rare congenital condition characterized by the underdevelopment of the eyes iris. ...

Contents

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