Aniridia

Children with aniridia can attend regular public schools, but it is important to alert the school’s visual impairment team to provide support for the child. Resources for early intervention at both school and home can also be very important.

Most children with isolated aniridia develop on pace with their peers, but a primary care provider should still track their development and make any necessary referrals.

Individuals with aniridia often have dilated pupils because the iris normally adjusts how much light reaches the pupil. Without this protection, the eye is especially sensitive to light.

As isolated aniridia inherited from a parent can appear in an affected child’s siblings, these siblings warrant a test as well. If a child affected with aniridia has no family history of the disorder, the risk of aniridia for her siblings and other family members is low. If the child is indeed the first in the family with aniridia, she has most likely experienced a random mutation to her PAX6 gene.

Online support groups are a good place to start. The Vision for Tomorrow Foundation has information on how to connect with other people who have aniridia or who are parents of children with aniridia. The Foundation also offers contact information to Debby Casher, a parent of a child with aniridia who can connect you with other parents or is also happy to "share her story and lend an ear." You can find her contact information here: https://www.visionfortomorrow.org/aniridia-get-support/. Additionally, there is a Facebook page that families use to ask questions and share experiences in the community known as UFA.

Affected individuals will need specialists, likely both an ophthalmologist and a medical geneticist, but for affected children a sensitive pediatrician experienced with the age-group is the best place to start. A pediatrician will likely be the one to make the required referrals to the aforementioned specialists; additional specialists one may see include cataract specialist, glaucoma specialist, and pediatric ophthalmologist.

Although aniridia lacks an official abbreviation, it can sometimes be found abbreviated "AN."

Preimplantation genetic diagnosis is a procedure where an embryo is created in a lab using the biological parents’ sperm and egg, and can then be screened for the already identified PAX6 mutation in the family. Once an embryo without a mutation is identified, it can be implanted into the mother and so the baby will not have aniridia. This can only be done if a mutation has already been identified.

Nystagmus is comprised of irregular, involuntary eye movements. These movements are seen in individuals with aniridia and are usually more frequent when they feel upset, excited or tired.

Aniridia is a genetic condition of the eye whereby part or all of the iris-the colored ring around the pupil-is absent.

A null point is a head position that provides an individual the best vision by most reducing the effects of nystagmus. To find one, vary the positions of one’s head to find the area of the retina that allows for the best focus.

Since aniridia is a condition where the iris of the eye is absent, most of the health problems associated with aniridia will be ocular features, that is, features associated with the eyes. These ocular features are cataracts (clouding of the eye’s lense), glaucoma (increased pressure in the eye), involuntary eye movements (nystagmus), or underdevelopment of the area behind the eye responsible for sharp central vision (foveal hypoplasia). These symptoms may progressively lead to vision loss without proper ophthalmologic management.

The PAX6 gene is responsible for producing the PAX6 protein, a protein that plays a role in both the embryonic development of the eyes, brain and spinal cord, and the later maintenance of the eyes. As a result, mutations of the PAX6 gene disrupt the production of this PAX6 protein. When faulty, the protein otherwise responsible for developing the iris before birth produces either an incomplete iris or none at all.

Known causes of aniridia are either mutations and deletions in the PAX6 gene, or deletions in the regions of the gene that controls PAX6. One commonly finds the terms "mutations," "changes" and "pathogenic variations" used interchangeably.

If someone is in fact homozygous for mutations in the PAX6 gene–if both of her genes are mutated–severe abnormalities result: deformed skull and facial bones, an absent or malformed nose, absent adrenal glands, central nervous system abnormalities, absence of one or both eyes, and neonatal death.

Four of the ways aniridia is clinically diagnosed are:

Some of the main symptoms of aniridia include a sensitivity to light, abnormal and/or misshapen pupils, and possibly a reduction in the sharpness of one’s vision.

Individuals may seek out genetic testing for several reasons. One reason is to confirm that a diagnosis of isolated aniridia really is isolated, rather than the result of a genetic syndrome as Wilms tumor-aniridia-genital anomalies-retardation (WAGR) that has aniridia as one of its features. If the aniridia is indeed part of a different syndrome, the affected individual may need additional screening and management. Another reason to seek testing is for future family planning. Knowing the genetic cause can allow for prenatal testing or even pre-implantation genetic diagnosis. A medical geneticist can be found by asking your doctor for a referral or looking on the American College of Medical Geneticists website. Genetic counselors can be found on the National Society of Genetic Counselors website.

The first, best thing to do is to get informed. The strongest advocate for a child reads information about aniridia on credible websites and using well-researched resources. Peer support is a must: many websites and support groups online can connect parents of children with aniridia in order to share their experiences and insights.

Instilling eye drops in infants with or without aniridia can be challenging, but there are ways to achieve this with minimal fuss. A good technique involves wrapping an infant in a blanket to secure her arms and legs, and lying her on her back with her head is between one’s knees to prevent movement. One can either place a drop at the corner of the child’s eye and wait until it settles in the eye when she opens he eyelid, or gently pull down her lower eyelid to create a small pouch for the drop.

The penetrance of aniridia is 100%: all those with the PAX6 gene mutation will show the clinical features of aniridia.

Just like with adults, aniridia in newborns can be detected through a simple eye exam by an experienced ophthalmologist.

One type of genetic test is available to check for deletions and another for mutations. A PAX6 sequence analysis checks for mutations, and deletion testing checks for deletions; as either are possible causes of aniridia, labs tend to perform both simultaneously.

As of 2019, there are several clinical trials for aniridia. For the most up to date information in clinical trial in the United States, visit clinicaltrials.gov. Support organizations such as https://www.visionfortomorrow.org/research also has information on current research.

There is no direct treatment of aniridia; rather, treating aniridia entails treating its various individual manifestations. Those affected should have regular eye exams to help assess and predict future visual functioning. Among the most commonly treated symptoms of aniridia are corrections of refractive errors and treatment of anisometropic amblyopia or strabismic amblyopia in childhood through occlusion therapy.

A prenatal diagnosis of aniridia is possible through one of two methods: a chorionic villi sampling in the first trimester or amniocentesis in the second trimester. Both procedures pose some risk to the pregnancy.

Patients with photophobia are able to go anywhere they feel comfortable with proper protection, using appropriate sunglasses or hats.

If a parent has Aniridia caused by a mutated PAX6 gene, a child has a 50% chance of inheriting Aniridia and a 50% chance of not.

An aniridia patient’s doctor should know that aniridia can be isolated or part and parcel to a genetic syndrome, as Wilms tumor-aniridia-genital anomalies-retardation (WAGR) syndrome. When accompanied by a syndrome, a patient requires additional screening and surveillance; for this reason, it is important to ask one’s physician if testing, treatment, or monitoring for WAGR syndrome is needed. Furthermore, a doctor should also know that some common treatments for the secondary symptoms of aniridia are actually contraindications for an affected individual.

Although a 100% penetrant, aniridia has variable expressivity, meaning its severity differs across those afflicted. Some will experience only mild symptoms, others moderate ones, and still others more severe symptoms.

People with aniridia need regular eye exams to prevent and promptly treat the different symptoms of aniridia. The frequency of these visits will vary depending on what an ophthalmologist decides and those eye problems a patient has.

How much someone’s vision is affected by aniridia depends on several factors. Lacking an iris does not cause blindness by itself, but rather depends on the extent of the disease and the exact parts of the eye affected. Predicting if a baby will lose vision in the future is difficult because ocular complications may occur in the future from the disease that may reduce someone’s functional vision. Some of the symptoms of aniridia such as nystagmus (repetitive involuntary eye movements) or recurrent glaucoma and cataract can reduce someone’s visual functioning.

Aniridia is an autosomal dominant disorder: it affects both males and females, and only one copy of the changed gene is needed to cause the disorder. While most affected individuals have an affected parent, in some the mutation is new.

Aniridia can be diagnosed using a clinical exam by an ophthalmologist, after which the exact cause may be determined with genetic testing.

For a genetic diagnosis, a sample from the patient is sent to a lab for an analysis of the PAX6 gene. This sample is most often blood, but some labs will also accept a saliva sample or a buccal swab.

When starting a support group, it may be best to recruit a co-leader or two who can follow along on the journey. Logistics include identifying potential members, naming the group, determining the time and place for meetings, and drafting a mission statement. After completing the basics, it is important to format the meetings and begin publicizing the support group.
Global Genes’ Toolkits also provides information on how to start a support group.

An optometrist and an ophthalmologist have different educational backgrounds. An ophthalmologist is a medical doctor who has gone to medical school and specializes in medical and surgical care of the eye. She can perform surgeries, prescribe eyeglasses, and treat any eye diseases. An optometrist is a doctor who went to optometry school, not medical school. An optometrist can also prescribe eyeglasses and drugs that treat eye diseases, but cannot perform surgery. An optometrist can, however, provide pre- and post-surgery care. A primary care doctor can refer patients with aniridia to right type of health care, and an optometrist can also make a referral to an ophthalmologist if needed.

You can always give money to support groups/foundations that support aniridia research:
The Vision for Tomorrow Foundation accepts donations online: https://www.visionfortomorrow.org/donate/
Aniridia Foundation International accepts donations for research involving aniridia: https://aniridiafnd.ejoinme.org/MyPages/DonationPage/tabid/92947/Default.aspx
Cornea research Foundation of America does research on different medical conditions including aniridia, and accepts donations year round: http://www.cornea.org/Donate.aspx

One of the ways to find clinical research on aniridia is to log on to clinicaltrials.gov and type in "Aniridia" in the Search for Studies bar. This will take you to a page displaying a list of clinical trials that are active, recruiting, or completed. Different support group pages such as The Vision for Tomorrow Foundation may also have lists of current and past research on aniridia.

Approximately one newborn in 100,000 to 1 in 50,000 is diagnosed with aniridia.

Photophobia is an issue for many with aniridia; they can be highly light-sensitive and feel pain or discomfort in bright lighting. Adults tend to protect themselves by squinting or avoiding certain lights, but children may need encouragement to wear hats or sunglasses. Also be sure to position children away from window light in their highchairs or car seats.

To obtain "Early Intervention Services" for a child with aniridia one needs to find the agency that corresponds to one’s home state. Visiting the National Dissemination Center for Children with Disabilities’ website provides information compiled for each state. Even if a child’s development is on track, these agencies can provide evaluations and important needed services.

Since aniridia is a rare condition, some doctors may not be very familiar with it. The Vision for Tomorrow Foundation suggests asking a doctor if they have experience with patients who have aniridia. This is important because some of the common treatments of the eye problems in aniridia may actually be contraindications in this case. The Vision for Tomorrow Foundation also suggests posting on the Facebook Page (United Families of Aniridia) one’s specific needs and requests from other aniridia patients and parents.

Every study for aniridia features different criteria children must meet to participate. If a child qualifies for a study, contacting someone responsible for recruitment and filling out the necessary forms are the likeliest steps forward.

Nystagmus can make it difficult for someone to focus on specific objects and see clearly. People can get used to nystagmus and find better positions for their head to reduce it.

People with aniridia can read text using their vision. Some choose to learn to read Braille to give their eyes some rest every now and then, or as a precaution for the future in case of a medical complication.

While aniridia does not worsen once the PAX6 protein ceases performing this developmental role, symptoms of aniridia such as glaucoma, cataracts and corneal pannus (chronic superficial keratitis) may adversely affect one’s eyesight later in life.

The risk of having aniridia with a change in the PAX6 gene is 100%.

Surgery is only necessary for those problematic features of aniridia that do not or could not respond to medication. Glaucoma is usually treated using medication therapy such as topical anti-glaucoma medication, and surgery is only reserved for eyes unresponsive to medical therapy.

Whether or not a patient needs special accommodations to read text depends on the extent of the aniridia. Some individuals may require larger text than usual, magnifiers or high contrast materials. These have now become easier to find with gadgets as e-readers and tablets.

Babies with aniridia require visual stimulation in the first few months of life. A caregiver should stimulate a child’s vision by surrounding her with colorful, visually interesting things. One can make the areas around her crib, her toys and the family’s clothes black, white, and primary colors for high contrast. Once a child has begun vision therapy, a therapist may also recommend activities to stimulate the child’s vision.

If both parents have Aniridia, a child may inherit two copies of the mutated PAX6 gene. This causes a more severe condition, and is fatal.

Depending on the extent of disease, some individuals with aniridia may be good candidates for special types of contacts that may help improve vision as well as reduce glare. It can also have a cosmetic benefit.

The ability to drive depends on the extent of the aniridia, and different states and countries have different requirements for drivers. It may be necessary to wear special device known as bioptic in order to drive.

Glasses can help patients with aniridia, but not completely. Glasses can improve vision and correct abnormalities with the lenses of the eye, correcting farsightedness or nearsightedness. They cannot, however, correct abnormalities with other structures of the eye that reduce vision, particularly the fovea.

None of a mother’s behaviors during pregnancy can induce or prevent aniridia.

Most healthcare providers will only offer prenatal testing for aniridia if a mutation has already been identified in the family. To learn more about prenatal testing for aniridia see a genetic counselor. Genetic counselors can be found on the National Society of Genetic Counselors website.

There are some genetic syndromes with which aniridia is associated. Both Wilms tumor-aniridia-genital anomalies-retardation (WAGR) syndrome and Gillespie syndrome include aniridia, but each are associated with further symptoms uncharacteristic of aniridia alone.

Regular surveillance is essential to maintaining optimal visual functioning for as long as possible. Recommended surveys include annual glaucoma screening, assessing intraocular pressure and audiological evaluations for those children whose hearing may be adversely affected. Syndrome-related aniridia requires further surveillance: children with WAGR syndrome require renal ultrasounds every three months until the age of 8 to screen for Wilms tumors, and individuals with Aniridic Fibrosis syndrome would need multiple further ocular procedures.

Select medical problems that result from aniridia may be treated: both glaucoma and corneal disease (aniridic keratopathy) warrant treatment, and lens opacities can be treated via cataract extraction.

Names attributed to aniridia include absent iris, congenital aniridia and irideremia.

Other clinical features are uncommon if the aniridia is isolated-that is, unassociated with another genetic syndrome. However, in rare cases individuals with aniridia may exhibit symptoms as diverse as developmental delay, behavioral issues and even problems detecting odors.

Support groups include Aniridia Foundation International (http://www.make-a-miracle.org/), Aniridia Network UK (https://aniridia.org.uk/), and The Vision for Tomorrow Foundation (https://www.visionfortomorrow.org/aniridia-get-support/).

Aniridia is something an individual is born with, but the different medical problems or features associated with the eye can occur at birth, or later in life over time.

Many with aniridia have expressed preference for ‘Julbo’ brand sunglasses, specifically the "looping brand" for their practicality and a feature that blocks out light from the sides. The Vision for Tomorrow Foundation has recommended the brand ‘Sunday Afternoons’ for having quality lightweight hats.

Other ocular conditions resemble aniridia. Some of these conditions include Rieger anomaly, Iris coloboma, and Gillespie syndrome–each distinct but similar conditions that also affect the iris.

Aniridia is most often an inherited genetic syndrome. However, not all mutations are inherited. Sometimes a new mutation can occur very early in a pregnancy, and one calls this condition sporadic aniridia. A person with sporadic aniridia can then pass it on to her children as well.