Rare Pulmonology News

Disease Profile

Coloboma of optic nerve

Prevalence
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.

Unknown

Age of onset

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ICD-10

#N/A

Inheritance

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

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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

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X-linked
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.

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

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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.

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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.

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Not applicable

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Other names (AKA)

Optic nerve head pits, bilateral congenital; Congenital coloboma of the optic nerve; Optic nerve coloboma

Summary

Coloboma of the optic nerve is a congenital eye abnormality in which the optic nerve (which carries images of what the eye sees to the brain) is incompletely formed. The condition may occur in one or both eyes. The degree of visual impairment varies widely depending on the severity and structures involved. Serous detachments of the retina commonly occur in affected people, with a high risk for extensive retinal detachment. The coloboma may be associated with other features, such as a small eye (microphthalmia) with or without a cyst; small cornea (microcornea); or coloboma of other eye structures. Although the condition is present from birth, diagnosis may be delayed since the coloboma is inside the eye and not visible by simple inspection. Coloboma of the optic nerve may occur sporadically, may be due to a genetic mutation and be inherited, or may occur as a feature of an underlying syndrome or other genetic condition. There is no treatment to correct an optic nerve coloboma, but low vision aids may be helpful for some people.[1][2][3]

Symptoms

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:
HPO ID
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance
0000006
Optic nerve coloboma
0000588
Retinal detachment
Detached retina
0000541

Cause

Colobomas are due to incomplete development of the eye. During the second month of development in utero, a seam-like structure called the optic fissure closes up to form the structures of the eye. When it doesn't fuse normally, it results in a coloboma in the affected location of the eye.[4]

A coloboma may occur sporadically, it may be inherited and due to mutations in various genes, or may occur as a feature of an underlying syndrome or other genetic condition. When an underlying syndrome or genetic condition is present, the cause is assumed to be the same as that of the underlying condition. For example, when an optic nerve coloboma occurs as part of renal coloboma syndrome, it is caused by mutations in the PAX2 gene.[3] Certain environmental factors affecting early development may also increase the risk for colobomas in general.[4]

Many genes involved in early eye development may be responsible for colobomas in general. While some of these genes have been identified, most of them remain unknown. Most genetic mutations associated with colobomas have been identified only in very small numbers of affected people.[4] Autosomal dominant inheritance has been reported.[3] One gene that has been associated with coloboma of the optic nerve specifically is the PAX6 gene.[5]

The PAX6 gene is part of a "family" of genes that are needed for forming tissues and organs during embryonic development, and for maintaining normal function of certain cells after birth. The genes in this family give the body instructions to make proteins that help control the activity of particular genes. It is thought that the PAX6 protein turns on (activates) genes involved in forming the eyes before birth, and regulating the actions of genes within many eye structures.[6]

Organizations

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 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.

    Where to Start

      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. 
      • PubMed is a searchable database of medical literature and lists journal articles that discuss Coloboma of optic nerve. Click on the link to view a sample search on this topic.

        Diagrams/Images

        • The Digital Reference of Ophthalmology provides an image and outlined description of optic nerve coloboma. Click on Digital Reference of Ophthalmology to view the information page.

          References

          1. Coloboma of the Optic Nerve. University of Arizona. 2015; https://disorders.eyes.arizona.edu/disorders/coloboma-optic-nerve.
          2. Karl C Golnik. Congenital anomalies and acquired abnormalities of the optic nerve. UpToDate. Waltham, MA: UpToDate; September, 2015;
          3. G N Dutton. Congenital disorders of the optic nerve: excavations and hypoplasia. Eye. 2004; 18:1038-1048.
          4. Coloboma. Genetics Home Reference. November, 2011; https://ghr.nlm.nih.gov/condition/coloboma.
          5. Marla J. F. O'Neill. Coloboma of Optic Nerve. OMIM. August 15, 2014; https://www.omim.org/entry/120430.
          6. PAX6. Genetics Home Reference. July, 2014; https://ghr.nlm.nih.gov/gene/PAX6.

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