Everything about Heterochromatic totally explained
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In anatomy,
heterochromia refers to a difference in
coloration, usually of the
irises but also of
hair or
skin.
Heterochromia (also known as a
heterochromia iridis or
heterochromia iridium) is an
eye condition in which one iris is a different color from the other (
complete heterochromia), or where part of one iris is a different color from the remainder (
partial heterochromia or
sectoral heterochromia). It is a result of the relative excess or lack of
pigment within an iris or part of an iris, which may be genetically
inherited or due to
mosaicism, or acquired by
disease or
injury.
Eye color, specifically the color of the irises, is determined primarily by the concentration and distribution of
melanin pigment within the iris tissues.
Consequently, anything affecting those factors may result in a difference of color being observed.
The affected eye may be hyperpigmented (hyperchromic) or hypopigmented (hypochromic). An excess of pigmentation is usually associated with
hyperplasia of the iris tissues, whereas a lack of pigmentation is associated with hypoplasia.
Partial or sectoral heterochromia is much less common than complete heterochromia and is typically found in
autosomally inherited disorders such as
Hirschsprung's disease and
Waardenburg syndrome. Famous comedian
Dan Aykroyd has heterochromia, as do singer/songwriter
Carly Simon, actresses
Kate Bosworth,
Elizabeth Berkley,
Mila Kunis,
Jane Seymour, actor
Christopher Walken, American
mixed martial artist
Jens Pulver, and Major League Baseball pitcher
Max Scherzer. Musician
David Bowie is often thought to have heterochromia, but this isn't the case as Bowie's eyes are both blue (his left pupil is permanently dilated due to a childhood injury).
Heterochromia in animals
Although seen in humans, heterochromia in which one iris differs in color from the other iris is more frequently observed in non-human species such as
cats (for example,
Japanese Bobtails and
Turkish Vans; white, shorthaired cats can be "
odd-eyed" with one copper or orange eye and one blue eye, and the
Turkish Angora),
dogs (for example,
Siberian Huskies as well as
Australian Shepherds,
Border Collies, and other breeds with
merle coats),
horses (so-called "wall-eyed" horses have one brown and one white or blue eye), and even
water buffalo.
Classification based on etiology
Heterochromia is classified primarily by onset: as either
genetic or acquired.
Although a distinction is frequently made between heterochromia that affects an eye completely or only partially (sectoral heterochromia), it's often classified as either
genetic (due to
mosaicism or
congenital) or acquired, with mention as to whether the affected iris or portion of the iris is darker or lighter.
Congenital heterochromia
Heterochromia that's congenital is usually inherited as an
autosomal dominant trait.
Abnormal iris darker
Abnormal iris lighter
Simple heterochromia — a rare condition characterized by the absence of other ocular or systemic problems. The lighter eye is typically regarded as the affected eye as it usually shows iris hypoplasia. It may affect an iris completely or only partially.
Congenital Horner's syndrome — sometimes inherited, although usually acquired
Waardenburg's syndrome
Piebaldism — similar to Waardenburg's syndrome, a rare disorder of melanocyte development characterized by a white forelock and multiple symmetrical hypopigmented or depigmented macules.
Hirschsprung's disease — a bowel disorder associated with heterochromia in the form of a sector hypochromia. The affected sectors have been shown to have reduced numbers of melanocytes and decreased stromal pigmentation.
Incontinentia pigmenti with results suggesting that there's more difficulty recognizing iris color changes in dark-eyed individuals.
Acquired Horner's syndrome — usually acquired, as in neuroblastoma, although sometimes inherited.
Neoplasm — Melanomas can also be very lightly pigmented, and a lighter colored iris may be a rare manifestation of metastatic disease to the eye.
Heterochromia has also been observed in those with Duane syndrome.
Chronic iritis Though not studied widely, Central Heterochromia is the rarest form of Heterochromia.
Eye colour is determined primarily by the concentration and distribution of melanin pigment within the iris tissues, Anything affecting those factors may result in a difference of colour being observed.
The human iris can be seen in a number of various colours. There are three true colors in the eyes that determine the outward appearance; brown, yellow, and grey. How much of each colour an individual has determines the appearance of his or her eye colour.
Eyes displaying Central Heterochromia are often referred to as "cat eyes" because of the appearance of a multi-coloured iris. Central Heterochromia appears to be prevalent in irises containing low amounts of melanin.Central Heterochromia doesn't label an eye as hazel. This is because the outer ring of an eye affected by Central Heterochromia is that iris' true colour.
The potential to acquire central heterochromia may be inherited genetically, though Central Heterochromia in itself is the condition where drug and toxic settlements in the body make the iris colour appear different from its basic predominant colour. These toxic signs that show in the iris indicate the amounts of the toxins the system has failed to eliminate.[
]Notable Heterochromiacs
Actor Christopher Walken
Actress Kate Bosworth
Actor Bradford Dillman (Captain McKay from the "Dirty Harry" series of movies)
National Hockey League centre Shawn Horcoff
Actress and political activist Casey Knowles, the "3 am girl" from the 2008 Democratic presidential campaigns.(External Link
)
Wrestler Kane
Actress Mila Kunis
Actor Joe Pesci(External Link)
Lead singer of Rise Against Tim McIlrath
Major league (Arizona Diamondbacks) pitcher Max Scherzer
Actress Jane Seymour (actress)
Lead singer of Fall Out Boy Patrick Stump
Singer/Songwriter Carly Simon
Actress Virginia Madsen
Actress Elizabeth Berkley
Missing child Madeline McCann (this was a feature of the Look for Maddie campaign)Further Information
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