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Encyclopedia > Leber's Hereditary Optic Neuropathy
Leber's hereditary optic neuropathy
ICD-10 H47.2
ICD-9 377.16

Leber’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. However, LHON is only transmitted through the mother as it is primarily due to mutations in the mitochondrial (not nuclear) genome and only the egg contributes mitochondria to the embryo. LHON is usually due to one of three pathogenic mitochondrial DNA (mtDNA) point mutations. These mutations affect nucleotide positions 11778, 3460 and 14484, respectively in the ND4, ND1 and ND6 subunit genes of complex I of the oxidative phosphorylation chain in mitochondria. Men cannot pass on the disease to their offspring. The following codes are used with International Statistical Classification of Diseases and Related Health Problems. ... The following is a list of codes for International Statistical Classification of Diseases and Related Health Problems. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Human eye cross-sectional view. ... A ganglion cell (or sometimes called a gangliocyte) is a type of neuron located in the retina that receives visual information from photoreceptors via various intermediate cells such as bipolar cells, amacrine cells, and horizontal cells. ... An axon, or nerve fiber, is a long slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neurons cell body or soma. ... In biology, mutations are changes to the genetic material (usually DNA or RNA). ... In biology the genome of an organism is the whole hereditary information of an organism that is encoded in the DNA (or, for some viruses, RNA). ... A human ovum An ovum (from Latin, loosely, egg or egg cell) is a female sex cell or gamete. ... In cell biology, a mitochondrion is an organelle found in the cells of most eukaryotes. ... Embryos (and one tadpole) of the wrinkled frog (Rana rugosa). ... The general structure of a section of DNA Deoxyribonucleic acid (DNA) is a nucleic acid —usually in the form of a double helix— that contains the genetic instructions specifying the biological development of all cellular forms of life, and most viruses. ... A nucleotide is a chemical compound that consists of a heterocyclic base, a sugar, and one or more phosphate groups. ... This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ... The electron transfer chain (also called the electron transport chain, ETC, e-train, or simply electron transport), is any series of protein complexes and lipid-soluble messengers that convert the reductive potential of energized electrons into a cross-membrane proton gradient. ... Oxidative phosphorylation is a biochemical process in cells. ...

Contents


Signs & symptoms

Clinically, there is an acute onset of visual loss, first in one eye, and then a few weeks later in the other. This eventually evolves to very severe optic atrophy and permanent decrease of visual acuity. In the acute stage lasting a few weeks, the affected eye demonstrates an edematous appearance of the nerve fiber layer especially in the arcuate bundles and enlarged or telangectatic and tortuous peripapillary vessels (microangiopathy). These main features are seen on fundus examination, just before or subsequent to the onset of visual loss. Examination reveals decreased visual acuity, loss of color vision and a cecocentral scotoma on visual field examination. This article or section does not cite its references or sources. ... Optic atrophy is a pathological term and somewhat misleading. ... Traditional Snellen chart used for visual acuity testing. ... Color vision is the capacity of an organism or machine to distinguish objects based on the wavelength of the light they reflect or emit. ... The word scotoma is derived from the Greek word for darkness. ... Perimetry is the systematic measurement of differential light sensitivity in the visual field by the detection of the presence of test targets on a defined background. ...


Diagnosis & management

The diagnosis is extremely difficult and usually requires a neuro-ophthalmological evaluation and/or blood testing for DNA assessment (that is available only in a few laboratories). Hence the incidence is probably much greater than appreciated. The prognosis is almost always that of continued very severe visual loss. There is no accepted treatment for this disease. A neuro-ophthalmologist is one of about 300 world-wide credentialled specialists in the combined fields of neurology and ophthalmology. ...


Leber’s hereditary optic neuropathy is sometimes confused with Leber's congenital amaurosis, which is a different disease also first described by Theodore Leber in the 19th century. 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. ...


Trivia

  • LHON 1 has an unusually high prevalence in Western Quebec, Canada, where it is referred to as Frenchman disease

In epidemiology, the prevalence of a disease in a statistical population is defined as the ratio of the number of cases of a disease present in a statistical population at a specified time and the number of individuals in the population at that specified time. ... Motto: Je me souviens (French: I remember) Official languages French Flower White garden lily Capital Quebec City Largest city Montreal Lieutenant-Governor Lise Thibault Premier Jean Charest (PLQ) Parliamentary representation  - House seat  - Senate seats 75 24 Area Total  - Land  - Water    (% of total)  Ranked 2nd 1,542,056 km² 1,183...

See also

Amaurosis (from greek for darkening, dark or obscure) is a weakness or loss of vision, the cause of which was at one time unknown. ... This is a partial list of human eye diseases and disorders. ...

External links


  Results from FactBites:
 
Lebers hereditary optic atrophy: Encyclopedia of Genetic Disorders (1522 words)
Lebers hereditary optic atrophy is a painless loss of central vision (blurring of objects and colors appearing less vivid) that usually begins between the ages of 25 and 35 (but can occur at any age) and leads to legal blindness.
The optic disc is the center part of the retina (back of the eye) and is where the clearest vision—both in detail and color—comes from.
In 1988 it was discovered that LHON is caused by a mutation in a mitochondrial gene.
LHON - Leber optic neuropathy (2128 words)
To ascertain the mitochondrial genetic etiology of the LHON in these families, both (a) the the nucleotide sequences of the seven mitochondrial genes encoding subunits of respiratory-chain complex I and (b) the mitochondrial cytochrome b gene were determined for representatives of both families.
Leber's hereditary optic neuropathy: heteroplasmy is likely to be significant in the expression of LHON in families with the 3460 ND1 mutation.
Leber's hereditary optic neuropathy (LHON) with mitochondrial ND4 gene mutation (11778) in a Thai patient.
  More results at FactBites »

 
 

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