Heterochromia is a difference in color, usually from iris but also from hair or skin. Heterochromia is determined by the production, delivery, and concentration of melanin (pigment). It may be inherited, or caused by a genetic mosaic, chimerism, disease, or injury. It happens to humans and certain dog and cat breeds.
Heterochromia eye ( heterochromia iridum or heterochromia iridis ) consists of three types. In complete heterochromia , one slice is a different color than the other. In or sectoral heterocromia , the part of one iris is a different color than the rest and eventually in the heterochromia center there is a ring around the pupil or maybe a different nail. color shines from pupil.
Although several causes have been put forward, the scientific consensus is that lack of genetic diversity is the main reason behind heterochromia. This is due to a gene mutation that determines the distribution of melanin in the 8-HTP pathway, which usually only becomes damaged by the homogeneity of the chromosome.
The eye color, especially the iris color, is mainly determined by the concentration and distribution of melanin. The affected eye may be hyperpigmented (hyperchromic) or hypopigmented (hypochromic). In humans, an increase in melanin production in the eye indicates hyperplasia of the iris tissue, whereas the lack of melanin suggests hypoplasia. The term is derived from the ancient Greek: ??????, hÃÆ' Â © teros which means different and ?????, chrÃÆ'³ma which means color.
Video Heterochromia iridum
Classification
Heterochromia is classified primarily by onset: either genetic or acquired. Although differences are often made between heterochromia which affects the eyes completely or only partially (sectoral heterochromia), it is often classified as genetic (due to mosaicism or congenital) or obtained, stating whether the iris or the affected part of the iris is darker or lighter. Most cases of heterochromia are hereditary, caused by certain diseases and syndromes. Sometimes one eye may change color following illness or injury.
Sectoral or Partial Heterochromia
In sectoral heterochromia, sometimes referred to as partial heterochromia, the same iris area contains two completely different colors. It is not known how rare sectoral heterochromia in humans is because there is no scientific evidence.
Iris is not normally darker
- Lisch nodules - hamartoma irises seen in neurofibromatosis.
- Ocular melanosis - a condition characterized by increased pigmentation of the uveal, episclera, and anterior chamber angle.
- Oculodermal melanocytosis (nevus of Ota)
- Pigment dispersion syndrome - a condition characterized by loss of pigmentation from posteriorly disseminated posterior surfaces intraocular and deposited on various intraocular structures, including the anterior surface of the iris. Sturge-Weber syndrome - a syndrome characterized by port-wine nevus nevus in the distribution of the trigeminal nerve, ipsilateral angiilateral ipsoma with intracranial calcification and neurological signs, and choroid angioma, often with secondary glaucoma.
Iris is not normal lighter
- Simple heterochromia - a rare condition characterized by the absence of other eye or systemic problems. A lighter eye is usually regarded as an affected eye because it usually indicates iris hypoplasia. This may affect the iris completely or only partially.
- Horner's congenital syndrome - sometimes inherited, although usually obtained
- Waardenburg syndrome - a syndrome in which heterochromia is expressed as bilateral iris hypochromia in some cases. A Japanese review of 11 children with albinism found that the condition exists. All have sectoral/partial heterochromia.
- Piebaldism - similar to Waardenburg syndrome, a rare melanocyte developmental disorder characterized by white clumps and hypopigmented macules or double symmetrical depigmentation.
- Hirschsprung's disease - a bowel disorder associated with heterochromia in the form of sector hypochromia. The affected sector has been shown to reduce the amount of melanocytes and decrease stromal pigmentation.
- Incontinentia pigmenti
- Parry-Romberg syndrome
Acquiring heterochromia
The reference to heterochromia is usually due to injury, inflammation, the use of certain eye drops that damage the iris, or tumors.
Abnormal slices darker
- Material deposition
- Siderosis - iron deposition in ocular tissue due to penetrating injury and foreign matter containing intraocular iron left behind.
- Hemosiderosis - long hifema (blood in the anterior chamber) after blunt trauma to the eye can cause iron deposition from blood products
- Specific eye drops - prostaglandin analogues (latanoprost, isopropyl unoprostone, travoprost, and bimatoprost) are used topically to decrease intraocular pressure in glaucoma patients. A concentric heterochromia has developed in some patients who use these drugs. The stroma around the sphincter's iris muscle becomes darker than the peripheral stroma. A stimulation of melanin synthesis in the melanocyte slices has been postulated.
- Neoplasm - Nevi and melanomatous tumors.
- Iridocorneal endothelium syndrome
- Irritation ectropion syndrome
Iris is not normal lighter
- Fuchs heterochromic iridocyclitis - a condition characterized by classless, asymptomatic uveitis in which the affected iris becomes hypochromic and has a diseased mark, looks like a moth. Heterochromia can be very subtle, especially in patients with brightly colored irides. This is often most easily seen during the day. The prevalence of heterochromia associated with Fuchs has been estimated in various studies with results indicating that there is more difficulty recognizing iris color changes in dark-eyed individuals.
- Experiencing Horner's syndrome - usually acquired, as in neuroblastoma, although sometimes inherited.
- Neoplasms - Melanomas can also be highly pigmented, and lighter-colored irises may be a rare manifestation of metastatic disease in the eye.
- Parry-Romberg syndrome - due to missing tissue.
Heterochromia has also been observed in those with Duane syndrome.
- Chronic irrititis
- Juvenile xanthogranuloma
- Leukemia and lymphoma
Central heterochromia
The center of heterochromia is an eye condition in which there are two colors on the same iris; the central zone (pupil) iris is a different color from the mid-peripheral zone (cilia), with the actual iris color is the outer color. (need reference)
Eye color is determined primarily by the concentration and distribution of melanin in the iris tissue. Although the process of determining eye color is not fully understood, it is known that the inherited eye color is determined by several genes. Environmental or acquired factors may alter these inherited properties.
Human slices can be seen in various colors. There are three original colors in the human eye that define the outward appearance: brown, yellow, and gray. The amount of each color that a person owns determines the appearance of eye color.
Central heterochemicals appear to be common in irises that contain low melanin amounts.
The famous case of a person with central heterochromia is Baroness RÃÆ'³zsika Edle von Wertheimstein, whose daughter writes: "She is a very beautiful woman... She has dark brown eyes, dark, but each eye has a purple ring, about a quarter of a inch of purple around these dark brown eyes. "
Maps Heterochromia iridum
In other animals
Although rarely seen in humans, complete heterochromia is more frequently observed in other species, where it almost always involves a blue eye. Blue eyes occur in white places, where there is no melanin of the skin and hair (see Leucism). These species include cats, especially breeds such as Turkish Van, Turkish Angora, Khao Manee and (rare) Japanese Bobtail. This so-called strange-eyed cat is white, or mostly white, with one normal eye (copper, orange, yellow, green), and one blue eye. Among dogs, complete heterochromia is often seen in Siberian Husky and several other breeds, usually Australian Shepherd Dog and Catahoula Leopard and rarely in Shih Tzu. Horses with complete heterochromia have one brown eye and one white, gray, or blue eye - a complete heterochromia is more common in horses with pinto dyes. Complete heterochromia also occurs in cows and even water buffalo. It can also be seen in ferrets with Waardenburg syndrome, although it can be very difficult to say at times such as the often midnight blue color of the night.
Sectoral heterochromia, usually sectoral hypochromia, is often seen in dogs, especially in breeds with mantle merle. This breed includes the Australian Shepherd, Border Collie, Collie, Shetland Sheepdog, Welsh Corgi, Pyrenean Shepherd, Mudi, Beauceron, Catahoula Cur, Dunker, Great Dane, Dachshund and Chihuahua. It also occurs in certain breeds that do not carry merle properties, such as Siberian Husky and rarely, Shih Tzu. There are examples of breeds of cats that have conditions such as Van paint.
Gallery
See also
References
External links
- Radial Radial Sunburst Patterns in the Right Eye of the Blue-Eyed Women Spotted
Source of the article : Wikipedia
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