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Cornea plana 2(CNA2)

MedGen UID:
346616
Concept ID:
C1857574
Disease or Syndrome
Synonyms: CNA2; CORNEA PLANA 2, AUTOSOMAL RECESSIVE
 
Gene (location): KERA (12q21.33)
 
Monarch Initiative: MONDO:0009014
OMIM®: 217300

Definition

Cornea plana is clinically characterized by reduced corneal curvature leading in most cases to hyperopia, hazy corneal limbus, and arcus lipoides at an early age. CNA2 is a severe form of the disorder, which is frequently associated with additional ocular manifestations (summary by Tahvanainen et al., 1996). For discussion of genetic heterogeneity of CNA, see CNA1 (121400). [from OMIM]

Clinical features

From HPO
Arcus senilis
MedGen UID:
8179
Concept ID:
C0003742
Finding
A hazy, grayish-white ring about 2 mm in width located close to but separated from the limbus (the corneoscleral junction). Corneal arcus generally occurs bilaterally, and is related to lipid deposition in the cornea. Corneal arcus can occur in elderly persons as a part of the aging process but may be associated with hypercholesterolemia in people under the age of 50 years.
Corneal opacity
MedGen UID:
40485
Concept ID:
C0010038
Finding
A reduction of corneal clarity.
Hypermetropia
MedGen UID:
43780
Concept ID:
C0020490
Disease or Syndrome
An abnormality of refraction characterized by the ability to see objects in the distance clearly, while objects nearby appear blurry.
Microphthalmia
MedGen UID:
10033
Concept ID:
C0026010
Congenital Abnormality
Microphthalmia is an eye abnormality that arises before birth. In this condition, one or both eyeballs are abnormally small. In some affected individuals, the eyeball may appear to be completely missing; however, even in these cases some remaining eye tissue is generally present. Such severe microphthalmia should be distinguished from another condition called anophthalmia, in which no eyeball forms at all. However, the terms anophthalmia and severe microphthalmia are often used interchangeably. Microphthalmia may or may not result in significant vision loss.\n\nPeople with microphthalmia may also have a condition called coloboma. Colobomas are missing pieces of tissue in structures that form the eye. They may appear as notches or gaps in the colored part of the eye called the iris; the retina, which is the specialized light-sensitive tissue that lines the back of the eye; the blood vessel layer under the retina called the choroid; or in the optic nerves, which carry information from the eyes to the brain. Colobomas may be present in one or both eyes and, depending on their size and location, can affect a person's vision.\n\nPeople with microphthalmia may also have other eye abnormalities, including clouding of the lens of the eye (cataract) and a narrowed opening of the eye (narrowed palpebral fissure). Additionally, affected individuals may have an abnormality called microcornea, in which the clear front covering of the eye (cornea) is small and abnormally curved.\n\nBetween one-third and one-half of affected individuals have microphthalmia as part of a syndrome that affects other organs and tissues in the body. These forms of the condition are described as syndromic. When microphthalmia occurs by itself, it is described as nonsyndromic or isolated.
Reduced visual acuity
MedGen UID:
65889
Concept ID:
C0234632
Finding
Diminished clarity of vision.
Cornea plana
MedGen UID:
576329
Concept ID:
C0344529
Congenital Abnormality
Cornea plana is an abnormally flat shape of the cornea such that the normal protrusion of the cornea from the sclera is missing. The reduced corneal curvature can lead to hyperopia, and a hazy corneal limbus and arcus lipoides may develop at an early age.
Decreased corneal thickness
MedGen UID:
473349
Concept ID:
C1096274
Finding
A decreased anteroposterior thickness of the cornea.
Sclerocornea
MedGen UID:
344000
Concept ID:
C1853235
Disease or Syndrome
A congenital anomaly in which a part or the whole of the cornea acquires the characteristics of sclera, resulting in clouding of the cornea.

Recent clinical studies

Prognosis

Roos L, Bertelsen B, Harris P, Bygum A, Jensen H, Grønskov K, Tümer Z
BMC Med Genet 2015 Jun 23;16:40. doi: 10.1186/s12881-015-0179-9. PMID: 26099342Free PMC Article

Clinical prediction guides

Roos L, Bertelsen B, Harris P, Bygum A, Jensen H, Grønskov K, Tümer Z
BMC Med Genet 2015 Jun 23;16:40. doi: 10.1186/s12881-015-0179-9. PMID: 26099342Free PMC Article

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