What Is ANIRIDIA?
What is Aniridia?
Note: The links will take you to a more detailed explanation of the terms, which are listed at the end of this document.
Aniridia by definitional terms means congenital absence or partial absence of the iris. However this is not the only feature of Aniridia, as will be discussed later.
Aniridia is rare. Its incidence is between 1/50,000 and 1/100,000. The genetic defect has been found to be a deletion on chromosome 11. It is an autosomal dominant condition in 2/3 of the cases. Approximately, a third of all cases of Aniridia are sporadic and these are often found to have cytogentically detectable deletions involving 11p13, which, if extensive enough, cause the WAGR contiguous gene syndrome .
As stated above, Aniridia is more than just being born without an Iris. Many aniridics have developmental and ocular abnormalities and may exhibit the presence of one or more of these associated ocular abnormalities:
all of which contribute to severe reduction in visual acuity.
For more detailed information on the subject of Aniridia, its associated conditions, and new research, please go to the Members' Area. If not currently a member, please register now so you can get the full benefit of the Aniridia Foundation Internationals resources.
Definitions:
- Aniridia
- The congenital absence or partial absence of the Iris. This condition usually carries with it other medical conditions.
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- Autosomal Dominant
- Means there is a familial or genetic tendency, i.e. one parent has Aniridia also.
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- Bilateral Amblyopia
- A reduction or dimness in vision.
- Congenital
- A person is born with this condition.
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- Corneal Pannus
- A scarring or clouding of corneal tissue which reduces visual acuity eventually to the point of only being able to see the contrast between light and dark. It is thought to happen to people with Aniridia due to the lack of working stem cells.
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- Cytogenetically Detectable
- Able to be detected through testing chromosomes (DNA)
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- Glaucoma
- The elevated intraocular pressure of the eyeball.
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- Iris
- The colored part of the eye that surrounds the black pupil in the center of the eye.
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- Nystagmus
- Constant, involuntary movement of eyeball. May be congenital and inapparent to the Aniridiac. Seen in bilateral amblyopia. It is as if the eye is searching for focus.
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- Sporadic
- Being born with Aniridia when neither parent exhibits the condition. No family history.
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- WAGR (Contiguous Gene Snydrome)
- Stands for the associated contitions possible.
- (W)ilms Tumor
- (A)niridia
- (G)enital/Urinary abnormalities
- (R)etardation)
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- Wilms Tumor
- A malignant kidney tumor usually appearing before age 6, but rare cases have seen it appear later. Most authorities seem to agree on a 3 month interval of ultrasound monitoring during the period of greatest risk, (birth to age 5) with a 6 month to 1 year interval thereafter. Consult your doctor.
