What is Axenfeld-Rieger Syndrome?
Axenfeld-Rieger syndrome is a group of disorders that mainly affects the development of the eye. Common eye symptoms include cornea defects and iris defects. People with this syndrome may have an off-center pupil (corectopia) or extra holes in the eyes that can look like multiple pupils (polycoria).
What are the symptoms of Axenfeld-Rieger Syndrome?
People with Axenfeld-Rieger syndrome typically have:
- Cornea defects, including a cloudy cornea or posterior embryotoxin
- Iris issues; typically iris stands, which is connective tissue that connects the iris with the lens
- Pupil issues, including corectopia, abnormally large or small pupils
- Extra pupils (polycoria)
- Strabismus (cross-eye)
- Cataracts (cloudy lens)
- Macular degeneration (eye disorder that causes vision loss)
- Coloboma (a hole in a structure in the eye)
About 50% of people with this syndrome develop glaucoma, which is a condition that increases pressure inside of the eye. This may cause vision loss or blindness.
What causes Axenfeld-Rieger Syndrome?
Axenfeld-Rieger syndrome is inherited in an autosomal dominant manner. Each child of an individual with the disorder has a 50% chance of inheriting the mutation.
There are three types of Axenfeld-Rieger syndrome and each has a different genetic cause.
- Axenfeld-Rieger syndrome type 1 is caused by mutations in the PITX2 gene.
- Axenfeld-Rieger syndrome type 3 is caused by mutations in the FOXC1 gene.
- The gene that causes Axenfeld-Rieger syndrome type 2 is not known, but it is located on chromosome 13.
How is Axenfeld-Rieger Syndrome diagnosed?
Axenfeld-Rieger syndrome is diagnosed by ophthalmologic and clinical examination. Associated systemic findings are supportive of diagnosis. Genetic testing can be used to confirm the diagnosis.
Differential diagnoses include iris hypoplasia (IH), primary congenital glaucoma (PCG) and Peters anomaly.
Absence of other corneal abnormalities, such as megalocornea, sclerocornea and corneal opacity are useful in distinguishing ARS from other anterior segment disorders. Antenatal diagnosis
If the disease-causing mutation has been identified in a family, prenatal testing for at-risk pregnancies is possible.
What are the treatments for Axenfeld-Rieger Syndrome?
If glaucoma is present, the goal of treatment is to decrease intra-ocular pressure (IOP). An annual ophthalmologic exam should be done using several specific exams to detect the presence of glaucoma.
Should glaucoma develop, eye drops are usually recommended before surgery.
Medications that might be prescribed include those that decrease aqueous output (beta-blockers, alpha-agonists and carbonic anhydrase inhibitors).
Surgery is performed if eye drops are not sufficient in lowering IOP. If surgery is necessary, the procedure of choice is trabeculectomy. Laser surgery may also be indicated. Patients with corectopia (pupil is off center and not located where it should be) and polycoria (more than one pupil is present in the eye) may experience too much sensitivity to light (photophobia), and contact lenses may be helpful.
If the person has additional findings, treatment will depend on the symptoms present, and may include surgery to correct facial or dental problems, heart surgery, or corrective surgery for the cases of hypospadia. Short stature due to a growth hormone deficiency may be treated with growth hormone.
Where can I find out more about Axenfeld-Rieger Syndrome?