Aniridia

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. 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. 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 genetic changes in the PAX6 gene and is inherited in an autosomal dominant pattern.

Genetic Mutations: Isolated aniridia is caused by genetic mutations, also known as pathogenic variants. Genetic mutations can be hereditary, when parents pass them down to their children, or they may occur randomly when cells are dividing. Genetic mutations may also result from contracted viruses, environmental factors, such as UV radiation from sunlight exposure, or a combination of any of these.

If you suspect you may have this disease, you may want to start collecting your family health history. Information such as other family members who have had similar symptoms, when their/your symptoms first appeared, or exposures to any potential disease-causing environmental factors should be discussed with your medical team.

Known Genetic Mutations: Isolated aniridia is caused by genetic mutations in the following known gene(s):

FOXC1, TRIM44, PAX6

Given these known genetic mutation(s), you may want to ask your health care team if genetic testing is right for you. Genetic tests are laboratory tests that use samples of blood, saliva, or other tissues to help identify changes in genes, chromosomes, or proteins. Genetic testing can help confirm or rule out a suspected genetic disease, or can provide other useful information to your health care team.

Yes. It is possible for a biological parent to pass down genetic mutations that cause or increase the chances of getting this disease to their child. This is known as inheritance. Knowing whether other family members have previously had this disease, also known as family health history, can be very important information for your medical team.

There are multiple ways, or patterns, a disease can be inherited depending on the gene(s) involved. Based on GARD’s current data, this disease can be inherited in the following pattern(s):

Autosomal Dominant: Autosomal means the gene involved is located on one of the numbered chromosomes. Dominant means that a child only needs to inherit one copy of the mutated gene, from either biological parent, to be affected by the disease.

People affected by an autosomal dominant disease have a 50% chance of passing on the mutated gene to their biological child.