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Disease Profile

Anterior segment dysgenesis

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Anterior segment ocular dysgenesis; ASOD; ASMD;


Congenital and Genetic Diseases; Eye diseases


Anterior segment dysgenesis (ASD) refers to a spectrum of disorders that affect the development of the front of the eye (the anterior segment), which includes the cornea, iris, ciliary body, and lens. The specific eye abnormalities (alone or in combination) vary depending on the subtype of ASD and genetic cause, and some types may also be associated with neurological abnormalities.[1][2][3] Glaucoma develops in approximately 60% of people with ASD, during infancy or much later.[4] Specific eye signs and symptoms of ASD may include:[1][2][3][5]

  • Underdevelopment of the iris (iris hypoplasia).
  • An enlarged or reduced cornea diameter.
  • Growth of new blood vessels (vascularization) and opacity in the cornea.
  • Posterior embryotoxon (a thickened and displaced Schwalbe's line).
  • Corectopia (displacement of the pupil).
  • Polycoria (more than one pupillary opening).
  • An abnormal iridocorneal angle (the angle formed by the iris and cornea).
  • Ectopia lentis (displacement of the lens).
  • Aphakia (absent lens).
  • Cataracts.
  • Anterior synechiae (when the iris adheres to the cornea).
  • Posterior keratoconus (thinning of the cornea).

Individual disorders within the ASD spectrum include Axenfeld-Rieger syndrome (which includes disorders formerly known as Axenfeld anomaly, Axenfeld syndrome, Rieger anomaly, Rieger syndrome, and iridogoniodysgenesis) and Peters anomaly.[4]

ASD may be caused by mutations in any of several genes and inheritance can be autosomal dominant or autosomal recessive, depending on the responsible gene.[2][5]

Treatment of signs and symptoms depends on the specific features in each person with ASD and may involve medications, eye surgery, or corrective lenses for poor vision.


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Aplasia/Hypoplasia of the iris
Absent/small iris
Absent/underdeveloped iris

[ more ]

Visual impairment
Impaired vision
Loss of eyesight
Poor vision

[ more ]

30%-79% of people have these symptoms
Corneal erosion
Damage to outer layer of the cornea of the eye
Corneal neovascularization
New blood vessel formation in cornea
Ectopia lentis
Keratoconjunctivitis sicca
Dry eyes
Macular hypopigmentation
Macular hypoplasia
Opacification of the corneal stroma
Optic nerve hypoplasia
Extreme sensitivity of the eyes to light
Light hypersensitivity

[ more ]

Drooping upper eyelid
Short palpebral fissure
Short opening between the eyelids
Squint eyes

[ more ]

5%-29% of people have these symptoms
Abnormality of the dentition
Abnormal dentition
Abnormal teeth
Dental abnormality

[ more ]

Abnormality of the genital system
Genital abnormalities
Genital abnormality
Genital anomalies
Genital defects

[ more ]

Abnormality of the hypothalamus-pituitary axis
Abnormality of the sense of smell
Abnormal sense of smell
Smell defect

[ more ]

Aplasia/Hypoplasia of the corpus callosum
Global developmental delay
Intellectual disability
Mental deficiency
Mental retardation
Mental retardation, nonspecific

[ more ]

Iris hypopigmentation
Light eye color
Bulging cornea
Cornea of eye less than 10mm in diameter
Involuntary, rapid, rhythmic eye movements
Optic nerve coloboma
Sensorineural hearing impairment
Umbilical hernia
1%-4% of people have these symptoms
Ocular anterior segment dysgenesis
Posterior polar cataract
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
Ocular hypertension
High eye pressure
Peters anomaly


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Organizations Providing General Support

        Learn more

        These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

        In-Depth Information

        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Anterior segment dysgenesis. Click on the link to view a sample search on this topic.


          1. Anterior Segment Dysgenesis. American Academy of Ophthalmology. https://www.aao.org/bcscsnippetdetail.aspx?id=42ca606e-d460-4bd1-91e7-6b1929600ab0. Accessed 2/22/2018.
          2. Bocchini CA. ANTERIOR SEGMENT DYSGENESIS 1; ASGD1. OMIM. January 26, 2017; https://www.omim.org/entry/107250.
          3. Bocchini CA. ANTERIOR SEGMENT DYSGENESIS 3; ASGD3. OMIM. January 26, 2017; https://www.omim.org/clinicalSynopsis/601631.
          4. Olitsky SE, Reynolds JD. Overview of glaucoma in infants and children. UpToDate. Waltham, MA: UpToDate; October 18, 2017; https://www.uptodate.com/contents/overview-of-glaucoma-in-infants-and-children.
          5. Bocchini CA. ANTERIOR SEGMENT DYSGENESIS 2; ASGD2. OMIM. January 26, 2017; 610256.