Aniridia: Overview

Aniridia is an eye disorder characterized by a complete or partial absence of the colored part of the eye (the iris). These iris abnormalities may cause the pupils to be abnormal or misshapen. Aniridia can cause reduction in the sharpness of vision (visual acuity) and increased sensitivity to light (photophobia).

People with aniridia can also have other eye problems. Increased pressure in the eye (glaucoma) typically appears in late childhood or early adolescence. Clouding of the lens of the eye (cataracts), occur in 50 percent to 85 percent of people with aniridia. In about 10 percent of affected people, the structures that carry information from the eyes to the brain (optic nerves) are underdeveloped. Individuals with aniridia may also have involuntary eye movements (nystagmus) or underdevelopment of the region at the back of the eye responsible for sharp central vision (foveal hypoplasia). Many of these eye problems contribute to progressive vision loss in affected individuals. The severity of symptoms is typically the same in both eyes.

Rarely, people with aniridia have behavioral problems, developmental delay, and problems detecting odors.

Source: GHR (NLM/NIH)1

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Summary

Aniridia is an eye disorder characterized by a complete or partial absence of the colored part of the eye (the iris) and is usually associated with foveal hypoplasia (underdevelopment of the part of the eye responsible for sharp central vision). This combination can lead to decreased visual acuity and involuntary eye movements (nystagmus) in affected infants. People with aniridia may also have other eye problems including increased pressure in the eye (glaucoma), clouding of the lens of the eye (cataracts), and abnormalities of the cornea. [1, 2] Many of these eye problems contribute to progressive vision loss in affected individuals. Occasionally, people with aniridia have behavioral problems, developmental delay, and problems detecting odors.[2] Aniridia may occur either as an isolated eye abnormality or as part of the Wilms tumor-aniridia-genital anomalies-retardation (WAGR) syndrome. Isolated aniridia may be caused by mutations in the PAX6 gene and is inherited in an autosomal dominant pattern.[2]

Last updated: 10/19/2016

Source: GARD (NIH)2

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What is aniridia?

Aniridia is a rare inborn disorder in which the tissue that makes up the iris (the coloured part of the eye) is underdeveloped or completely missing. This means that the eye is not able to adjust to differing levels of light. Aniridia affects both eyes and causes poor vision and increased sensitivity to light. The disorder may be associated with other changes to other parts of the eye, either from birth or developing over time. Other senses may also be affected, including reduced sense of smell and taste, and hearing difficulties.

Aniridia is almost always caused by a mutation (change) in a gene named PAX6, which is involved in the development of the eye and other tissues. Patients may also have other genetic problems.

Aniridia is a long-term debilitating condition due to progressive loss of sight.

Source: EMA (EU)3

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Summary

Congenital absence of the iris. [from HPO]

Source: GTR (NCBI/NIH)4

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Aniridia: A rare genetic inherited abnormality characterized by the partial or complete absence of the iris of the eye.5

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Aniridia: A congenital abnormality in which there is only a rudimentary iris. This is due to the failure of the optic cup to grow. Aniridia also occurs in a hereditary form, usually autosomal dominant.6

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Aniridia: Congenital absence of the iris.7

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Aniridia is a congenital ocular malformation characterized by the complete or partial absence of the iris. It can be isolated or part of a syndrome (isolated and syndromic aniridia; see these terms).8

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References

  1. Source: GHR (NLM/NIH): ghr.nlm.nih.gov/ condition/ aniridia
  2. Source: GARD (NIH): rarediseases.info.nih.gov/ diseases/ 5816/ aniridia
  3. Source: EMA (EU): ema.europa.eu/ ema/ index.jsp? curl=pages% 2Fmedicines% 2Fhuman% 2Forphans% 2F2015% 2F11% 2Fhuman_orphan_001656.jsp& mid=WC0b01ac058001d12b
  4. Source: GTR (NCBI/NIH): ncbi.nlm.nih.gov/ gtr/ conditions/ CN000492/ 
  5. Source: NCI Thesaurus
  6. Source: MeSH (U.S. National Library of Medicine)
  7. Source: Human Phenotype Ontology
  8. Source: Monarch Initiative

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.