Aniridia - Symptoms, Causes, Treatment | NORD (2023)

Disease Overview

Summary

Aniridia is a rare condition characterized by abnormal development of the iris of the eye. The iris is the circular, colored part in the middle of the eyeball. The center of the iris is known as the pupil. The iris can control the size of the pupil, which regulates the amount of light that enters the eye. Aniridia is a condition in which the iris is either partly or completely missing. Various forms of aniridia have been identified. Each form can be determined by what additional symptoms are present.

• View Full Report
• Print / Download as PDF

• Next section >

• < Previous section
• Next section >

Synonyms

• irideremia

• < Previous section
• Next section >

• < Previous section
• Next section >

Signs & Symptoms

Aniridia is marked by partial or complete absence of the iris of the eye. Vision is preserved in some patients with mild cases of aniridia. This condition occurs when the iris fails to develop normally before birth in one or both eyes. Typically, aniridia can be seen from birth. Aniridia can occur as a single abnormality or can be one of many symptoms in an underlying condition.

Isolated aniridia: Isolated aniridia is the partial or complete absence of the iris from birth. Some people with this type of aniridia may be unaware of any eye problems because pupils appear normal and usually only one eye is mildly affected. In more severe cases, isolated aniridia can cause vision problems later in life. Accompanying symptoms may include clouding of the crystalline lens of the eye (cataracts), gradual loss of vision due to increased pressure inside the eyeball which may be accompanied by varying degrees of pain (glaucoma) or superficial clouding of the cornea (corneal pannus). Rapid involuntary movement of the eyeball (nystagmus) and underdevelopment of the fovea area of the retina (which controls acute vision) may also occur. These accompanying symptoms can make vision cloudy or blurry.

Gillespie syndrome: Symptoms of Gillespie syndrome include aniridia, intellectual disability, and ataxia (lack of coordination of muscle movements). (For more information choose “Gillespie” as your search term in the Rare Disease Database.)

WAGR syndrome: WAGR stands forWilms’ tumor (a type of kidney tumor),Awanted,Genitourinary abnormalities, andRetardation (now called “Intellectual disability”). WAGR syndrome can also be associated with obesity. WAGR syndrome can present with some or all of these symptoms. (For more information choose “Wilms” as your search term in the Rare Disease Database.)

• < Previous section
• Next section >

• < Previous section
• Next section >

Causes

Most forms of isolated aniridia are caused by harmful changes (mutations) in thePAX6gene causing it to not work normally. This condition typically follows an autosomal dominant pattern. Most people with aniridia have a parent with aniridia. Some patients appear to have a spontaneous, new genetic variant.

Gillespie syndrome is a caused by harmful gene changes in in theITPR1gene. Gillespie syndrome follows an autosomal dominant pattern, or it can occur as a new genetic change.

WAGR syndrome is mainly caused by missing genetic information along chromosome 11. This missing genetic information sometimes encompasses thePAX6andWT1genes. WAGR syndrome gene deletions can occur in a dominant pattern. WAGR syndrome gene deletions can also occur for the first time in the affected individual.

We all have two copies of every gene. Dominant genetic disorders occur when only a single copy of a non-working gene is necessary to cause a particular disease. The non-working gene can be inherited from either parent or can be the result of a new changed (mutated) gene in the affected individual. The risk of passing the non-working gene from an affected parent to an offspring is 50% for each pregnancy. The risk is the same for males and females.

Sometimes a genetic cause for aniridia cannot be identified.

• < Previous section
• Next section >

• < Previous section
• Next section >

Affected populations

All types of aniridia affect males and females in equal numbers. This disorder is thought to occur in approximately 1 in 40,000 to 96,000 live births in the United States.

• < Previous section
• Next section >

• < Previous section
• Next section >

Disorders with Similar Symptoms

Symptoms of the following disorders can be similar to those of aniridia. Comparisons may be useful in helping your doctor find a diagnosis:

Irido goniodysgenesis is a genetic eye structure disorder. People with this disorder are born with underdevelopment of the foundation substance (stroma) of the iris. Glaucoma also occurs followed by the iris changing to a lighter color. Glaucoma is a vision disorder marked by gradual loss of vision and increased pressure inside the eyeball. It may be result in varying degrees of pain.

Rieger syndrome, also known as Irido gonodysgenesis with somatic anomalies, is characterized by incorrect development of the middle layer of the cornea and iris. There may also be abnormalities in the pupil, which is the opening that regulates the amount of light entering the eyeball. The edges of the cornea are clouded at birth and glaucoma also occurs.

Hereditary juvenile glaucoma is a genetic vision disorder which may be present at birth. However, onset of symptoms can occur later in childhood or adolescence. Glaucoma is characterized by diminished clear vision along with increased pressure with possible and variable pain of inside the eyeball.

• < Previous section
• Next section >

• < Previous section
• Next section >

Standard Therapies

Treatment
Treatment of aniridia is usually directed at improving and preserving vision. Drugs or surgery may be helpful for glaucoma and/or cataracts. Contact lenses may be beneficial in some cases. When a genetic cause cannot be identified, patients should be evaluated for the possibility of the development of Wilms’ tumor. (For more information on this disorder, please choose “Wilms” as your search term in the Rare Disease Database.)

In 2018, the FDA approved the first artificial iris, a surgically implanted device to treat adults and children with aniridia. This device may help to reduce light sensitivity and glare and improve the cosmetic appearance of the eye.

Genetic counseling is recommended. Other treatment is symptomatic and supportive.

• < Previous section
• Next section >

• < Previous section
• Next section >

Clinical Trials and Studies

Information on current clinical trials is posted on the Internet atwww.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Toll-free: (800) 411-1222
TTY: (866) 411-1010
Email:[emailprotected]

Some current clinical trials also are posted on the following page on the NORD website:
https://rarediseases.org/living-with-a-rare-disease/find-clinical-trials/

For information about clinical trials sponsored by private sources, contact:
http://www.centerwatch.com/

For information about clinical trials conducted in Europe, contact:
https://www.clinicaltrialsregister.eu/

• < Previous section
• Next section >

• < Previous section
• Next section >

References

TEXTBOOKS
Lauderdale JD. Aniridia. In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:640.

REVIEW ARTICLES
Wawrocka A, Krawczynski MR. The genetics of aniridia – simple things become complicated. J Appl Genet. 2018;59(2):151‐159.

Lim H, Kim D, Kim H. PAX6 aniridia syndrome. Curr Opin Ophthalmol. 2017;28(5):436-447.

Hingorani M, Hanson I, van Heyningen V. Aniridia. Eur J Hum Genet. 2012;20(10):1011-1017. doi:10.1038/ejhg.2012.100

JOURNAL ARTICLES
Hall HN, Williamson KA, FitzPatrick DR. The genetic architecture of aniridia and Gillespie syndrome. Hum Genet. 2019;138(8-9):881-898. doi:10.1007/s00439-018-1934-8.

Saying aye to the artificial iris. Nat Biotechnol. 2018;36(7):565.

Sannan NS, Gregory-Evans CY, Lyons CJ, et al. Correlation of novel PAX6 gene abnormalities in aniridia and clinical presentation. Can J Ophthalmol. 2017;52(6):570-577. doi:10.1016/jcjo.2017.04.006

Weissbart SB, Ayres BD. Management of aniridia and iris defects: an update on iris prosthesis options. Curr Opin Ophthalmol. 2016;27(3):244-249. doi:10.1097/ICU.0000000000000253

Laghmari M, et al. Bilateral congenital aniridia: 5 case reports. J Fr Ophthalmol. 2004;27:385–91.

Zumkeller W, Orth U, Gal A. Three novel PAX6 mutations in patients with aniridia. Mol Pathol. 2003;56:180-3.

Churchill AJ, et al. Prenatal diagnosis of aniridia. Ophthalmology. 2000;107:1153–56.

Chao LY, et al. Mutation in the PAX6 gene in twenty patients with aniridia. Hum Mutat. 2000;15:332-39.

Hartmann RW Jr, et al. Picture of the month. Congenital aniridia. Arch Pediatr Adolesc Med. 2000;154:525–26.

Tanzer DJ, et al. Black iris-diaphragm intraocular lens for aniridia and aphakia. J Cataract Refract Surg. 1999;25:1548-51.

Osher RH, et al. Cataract surgery combined with implantation of an artifical iris. J Cataract Refract Surg. 1999;25:1540-47.

Chen TC, et al. Goniosurgery for prevention of aniridic glaucoma. Arch Ophthalmol. 1999;117:1144-48.

INTERNET
Mosaic M, Hingorani M, Moore AT. PAX6-Related Aniridia. 2003 May 20 [Updated 2018 Oct 18]. In: Adam MP, Ardinger HH, Pagon RA, et al., editors. GeneReviews® [Internet]. Seattle (WA): University of Washington; 1993-2020. Available from:https://www.ncbi.nlm.nih.gov/books/NBK1360/Accessed July 22, 2020.

McKusick VA, ed. Online Mendelian Inheritance in Man (OMIM). Baltimore. MD: The Johns Hopkins University; Entry No: 106210; Last Update: 10/4/2016.https://www.omim.org/entry/106210#Accessed Jul 22, 2020.

• < Previous section
• Next section >

Programs & Resources

• Assistance Programs
• Patient Organizations