National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Congenital microcoria


Other Names:
Microcoria, congenital; MCOR; Congenital miosis; Microcoria, congenital; MCOR; Congenital miosis; Miosis, congenital; Pinhole pupils See More
Categories:
Congenital microcoria is a rare eye disorder affecting the development of the irises. It is characterized by absence or incomplete development of the iris dilator muscles (also called the pupil dilator muscles), making the pupils unable to dilate (widen).[1] People with congenital microcoria have small pupils (with a diameter less than 2 millimeters) that dilate poorly or not at all, even when pupil-dilating medicines (eye drops) are put on the eye.[1][2] The disorder is also often associated with nearsightedness, and glaucoma in childhood or early adulthood.[1][3][4]

Congenital microcoria that is not associated with an underlying syndrome is caused by a small, missing piece of genetic material (deletion) around a region of chromosome 13 designated as 13q32.[1][2] This region contains several genes, although it appears the exact gene or genes in the region responsible for congenital microcoria are still under investigation.[1] Inheritance is autosomal dominant.[1][2][3] Congenital microcoria is also a feature of autosomal recessive Pierson syndrome, caused by mutations in the LAMB2 gene.[4]

Standard treatment guidelines for congenital microcoria have not been established, but glaucoma usually requires medicine or surgery to lower pressure within the eyes. Eye glasses or contacts may be used for nearsightedness.[4]
Last updated: 2/20/2018

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.

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Medical Terms Other Names
Learn More:
HPO ID
5%-29% of people have these symptoms
Glaucoma 0000501
1%-4% of people have these symptoms
Ocular hypertension
High eye pressure
0007906
Percent of people who have these symptoms is not available through HPO
Autosomal dominant inheritance 0000006
Hypoplasia of the iris dilator muscle 0008345
Microcoria 0025492
Miosis
Constricted pupils
Pupillary constriction
[ more ] 		0000616
Myopia
Close sighted
Near sighted
Near sightedness
Nearsightedness
[ more ] 		0000545
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Last updated: 7/1/2020

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • The Centers for Mendelian Genomics program is working to discover the causes of rare genetic disorders. For more information about applying to the research study, please visit their website.

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

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 Congenital microcoria. Click on the link to view a sample search on this topic.

Diagrams/Images

  • A diagram of the eye can be found by visiting MedlinePlus, the National Library of Medicine Web site designed to help you research your health questions. Click on MedlinePlus to view the diagram.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Fares-Taie L, Gerber S, Tawara A, et al. Submicroscopic deletions at 13q32.1 cause congenital microcoria. Am J Hum Genet. April 2, 2015; 96(4):631-639. https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/25772937/.
  2. O'Neill MJF. MICROCORIA, CONGENITAL. OMIM. May 14, 2015; http://www.omim.org/entry/156600.
  3. Congenital microcoria. Orphanet. http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=566. Accessed 2/20/2018.
  4. Microcoria, congenital. The University of Arizona Health Sciences Center. http://disorders.eyes.arizona.edu/disorders/microcoria-congenital. Accessed 2/20/2018.