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Megalocornea (MGCN, MGCN1) is an extremely rare nonprogressive condition in which the
Megalocornea
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An Infant With Enlarged Corneas
- medscape {{Congenital malformations and deformations of eye Congenital disorders of eyes
Megalocornea (MGCN, MGCN1) is an extremely rare nonprogressive condition in which the cornea
The cornea is the transparency (optics), transparent front part of the eyeball which covers the Iris (anatomy), iris, pupil, and Anterior chamber of eyeball, anterior chamber. Along with the anterior chamber and Lens (anatomy), lens, the cornea ...
has an enlarged diameter
In geometry, a diameter of a circle is any straight line segment that passes through the centre of the circle and whose endpoints lie on the circle. It can also be defined as the longest Chord (geometry), chord of the circle. Both definitions a ...
, reaching or exceeding 13 mm. It is thought to have two subforms, one with autosomal inheritance and the other X-linked (Xq21.3-q22). The X-linked form is caused by a mutation in a gene '' CHRDL1'' which encodes Chordin-like 1 protein, also its more common and males generally constitute 90% of cases.
It may be associated with Alport syndrome
Alport syndrome is a genetic disorder affecting around 1 in 5,000–10,000 children, characterized by glomerulonephritis, end-stage kidney disease, and hearing loss. Alport syndrome can also affect the eyes, though the changes do not usually affec ...
, Craniosynostosis
Craniosynostosis is a condition in which one or more of the fibrous sutures in a young infant's skull prematurely fuses by turning into bone (ossification), thereby changing the growth pattern of the skull. Because the skull cannot expand perpe ...
, Dwarfism
Dwarfism is a condition of people and animals marked by unusually small size or short stature. In humans, it is sometimes defined as an adult height of less than , regardless of sex; the average adult height among people with dwarfism is . '' ...
, Down syndrome, Parry–Romberg syndrome
Parry–Romberg syndrome (PRS) is a rare disease presenting in early childhood characterized by progressive shrinkage and degeneration of the tissues beneath the skin, usually on only one side of the face (hemifacial atrophy) but occasionally ...
, Marfan syndrome
Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those with the condition tend to be tall and thin, with dolichostenomelia, long arms, legs, Arachnodactyly, fingers, and toes. They also typically ha ...
, Mucolipidosis
Mucolipidosis is a group of inherited metabolic disorders that affect the body's ability to carry out the normal turnover of various materials within cells.
When originally named, the mucolipidoses derived their name from the similarity in p ...
, Frank–ter Haar syndrome, Crouzon syndrome, Megalocornea mental retardation syndrome, etc.
Clinical features
Eyes are usually highlymyopic
Myopia, also known as near-sightedness and short-sightedness, is an eye condition where light from distant objects focuses in front of, instead of on, the retina. As a result, distant objects appear blurry, while close objects appear normal. ...
. There may be 'with the rule' astigmatism
Astigmatism is a type of refractive error due to rotational asymmetry in the eye's refractive power. The lens and cornea of an eye without astigmatism are nearly spherical, with only a single radius of curvature, and any refractive errors ...
. Lens
A lens is a transmissive optical device that focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements'') ...
may be luxated due to zonular stretching.In rare cases, it might be associated with intellectual disabilities.
References
External links
Megalocornea
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eMedicine
eMedicine is an online clinical medical knowledge base founded in 1996 by doctors Scott Plantz and Jonathan Adler, and computer engineers Joanne Berezin and Jeffrey Berezin. The eMedicine website consists of approximately 6,800 medical topic revi ...
ophthalmology; May 15, 2009; Thomas A Oetting, MD, Mark A Hendrix, MDAn Infant With Enlarged Corneas
- medscape {{Congenital malformations and deformations of eye Congenital disorders of eyes