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Genetic and Rare Diseases Information Center (GARD)

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Microcoria, congenital

Other Names for this Disease
  • Congenital microcoria
  • Congenital miosis
  • MCOR
  • Miosis, congenital
  • Pinhole pupils
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Your Question

Can you provide me with more information on congenital microcoria? Can this condition be treated and what might the long term effects be?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is congenital microcoria?

Congenital microcoria is a rare anomaly of the pupils. It is characterized by pupils of less than 2 mm diameter and is caused by the underdevelopment of the dilator pupillae muscle of the iris. This anomaly is associated with nearsightedness and glaucoma.[1][2]
Last updated: 7/19/2013

What are the symptoms of congenital microcoria?

Symptoms of congenital microcoria include small pupil size (< 2 mm), iris transillumination defects, and reduced or absent response to mydriatic drugs.[1]
Last updated: 7/19/2013

Is congenital microcoria associated with other conditions?

Congenital microcoria is thought to be most strongly correlated with glaucoma and nearsightedness.[2] In one large family it was also associated with goniodysgenesis (a eye abnormality involving the fluid in the eye). In addition, many eye conditions coexist with microcoria including congenital iris ectropion, embryotoxon, and Peters anomaly.[1][2]
Last updated: 7/19/2013

Is congenital microcoria genetic?

Both inherited and sporadic cases of congenital microcoria have been reported in the medical literature. Studies of families with this anomaly suggests an autosomal dominant mode of inheritance.[1]
Last updated: 7/19/2013

What are the long term effects of microcoria and how might microcoria be treated?

We were unable to find information in the medical literature regarding the long term effects of microcoria or its management. We encourage you to speak with a healthcare provider experienced in the management of rare eye disorders. The American Association of Eye and Ear Hospitals provides a list of member clinics and the Eye Research Network provides a list of eye research facilities that may be helpful as you search for clinics. Click on the links to view the lists. Please note that the lists are not exhaustive of all specialty and research eye clinics within the United States or abroad.

In addition, the U.S. National Institutes of Health, through the National Library of Medicine, developed to provide patients, family members, and members of the public with current information on clinical research studies. While there are no current studies involving microcoria, some studies about suspected genetic eye diseases have been completed. Click on the titles below to view results and learn more about possible future studies.

Screening for Studies on Inherited Eye Disease

Evaluation and Treatment of Pediatric, Developmental, and Genetic Eye Diseases

You can also visit the Research section of this webpage to learn more about participating in clinical trials on this condition.

Last updated: 7/19/2013

  • Rouillac C, Roche O, Marchant D, Bachner L, Kobetz A, Toulemont PJ, Orssaud C, Urvoy M, Odent S, Le Marec B, Abitbol M, Dufier JL. Mapping of a Congenital Microcoria Locus to 13q31-q32. Am. J. Hum. Genet. 1998;
  • Ramprasad VL, Sripriya S, Ronnie G, Nancarrow D, Saxena S, Hemamalini A, Kumar D, Vijaya L, Kumaramanickavel G. Molecular Vision. 2005; Accessed 3/17/2008.