Cone dystrophy

Title

Categories:

Congenital and Genetic Diseases; Eye diseases

Summary Summary

Cone dystrophy is a general term for a group of rare eye disorders that affect the cone cells of the retina. Cone cells allow a person to see color and fine detail, and they work best in bright light. The cone dystrophies can cause a variety of symptoms such as decreased visual clarity when looking straight ahead, a reduced ability to see colors, and an increased sensitivity to light.^[1] There are two main subtypes of cone dystrophy, called stationary cone dystrophy and progressive cone dystrophy. The age when symptoms begin, the type and severity of symptoms, and the progression of symptoms are all very different between individuals, even between people with the same type of cone dystrophy.^[1] Mutations in many genes have been found to cause cone dystrophy, and the condition can be inherited in an autosomal dominant, autosomal recessive, or x-linked manner.^[2]

Last updated: 7/1/2013

Symptoms Symptoms

The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.

Signs and Symptoms	Approximate number of patients (when available)
Abnormal electroretinogram	Very frequent (present in 80%-99% of cases)
Abnormality of color vision	Very frequent (present in 80%-99% of cases)
Abnormality of retinal pigmentation	Very frequent (present in 80%-99% of cases)
Photophobia	Very frequent (present in 80%-99% of cases)
Visual impairment	Very frequent (present in 80%-99% of cases)

Last updated: 7/1/2017

Diagnosis Diagnosis

The diagnosis of cone dystrophy is made based upon the presence of characteristic symptoms, a detailed family history, a thorough clinical evaluation and a number of supporting tests. While exams that measure visual acuity, perception of color, and field of vision are used to arrive at a proper diagnosis, an electroretinogram (ERG) is used to confirm the diagnosis.^[3]^[4]

During an ERG, eye drops are used to numb the eye before a special contact lens recorder is placed on the eye. Then a series of flashes of light are used to stimulate the retina. Doctors can then measure the electrical response of the rods and cones to the light. The test is performed twice – once in bright room and again in a dark room. A weak of absent signal of cone cells indicates cone dystrophy.^[3]^[4] More details about the diagnosis of cone dystrophy can be accessed through the University of Michigan Kellogg Eye Center.

Last updated: 9/2/2014

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Organizations Organizations

Nonprofit support and advocacy groups bring together patients, families, medical professionals, and researchers. These groups often raise awareness, provide support, and develop patient-centered information. Many are the driving force behind research for better treatments and possible cures. They can direct people to research, resources, and services. Many groups also have experts who serve as medical advisors. Visit their 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

American Foundation for the Blind
2 Penn Plaza, Suite 1102
New York, NY 10121
Toll-free: 800-232-5463
Telephone: 212-502-7600
Fax: 888-545-8331
E-mail: afbinfo@afb.net
Website: http://www.afb.org/
Foundation Fighting Blindness
7168 Columbia Gateway Drive, Suite 100
Columbia, MD 21046
Toll-free: 800-683-5555
Telephone: 410-423-0600 (local)
TTY: 800-683-5551
E-mail: info@fightblindness.org
Website: http://www.blindness.org
Lighthouse International
111 E 59th Street
New York, NY 10022-1202
Toll-free: 800-829-0500
Telephone: 212-821-9200
TTY: 212-821-9713
Fax: 212-821-9707
E-mail: info@lighthouse.org
Website: http://www.lighthouse.org
Retina International
Ausstellungsstrasse 36
CH-8005 Zurich
Switzerland
Telephone: + 41 (0) 44 444 10 77
Fax: + 41 (0) 44 444 10 70
E-mail: christina.fasser@retina-international.org
Website: http://www.retina-international.org

Do you know of an organization? Send us your suggestions.

Learn More 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

The National Organization of Rare Diseases (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.
University of Michigan Kellogg Eye Center has a booklet on "Understanding Cone Dystrophy" for patients and their families.

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.
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 Cone dystrophy. Click on the link to view a sample search on this topic.

Related Diseases Related Diseases

The following diseases are related to Cone dystrophy. If you have a question about any of these diseases, you can contact GARD.

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References References

Heckenlively J. Cone Dystrophy. NORD. 2010; https://rarediseases.org/rare-diseases/cone-dystrophy/.
Simunovic, M.P., Moore, A.T. The cone dystrophies. Royal College of Ophthalmologists. 1998; http://www.nature.com/eye/journal/v12/n3b/pdf/eye1998145a.pdf. Accessed 6/19/2013.
Heckenlively J. Cone Dystrophy. National Organization for Rare Disorders (NORD). 2010; http://www.rarediseases.org/rare-disease-information/rare-diseases/byID/847/viewAbstract. Accessed 9/2/2014.
Openshaw A, Branham K, Heckenlively J. Understanding Cone Dystrophy. University of Michigan Kellogg Eye Center. February 2008; http://www.kellogg.umich.edu/patientcare/downloads/Understand-Cone-Dystrophy.pdf. Accessed 9/2/2014.