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

Cone-rod dystrophy

Cone-rod dystrophy (CRD) is a group of inherited eye disorders that affect the light sensitive cells of the retina called the cones and rods. People with this condition experience vision loss over time as the cones and rods deteriorate.[1][2] Initial signs and symptoms that usually occur in childhood may include decreased sharpness of vision (visual acuity) and abnormal sensitivity to light (photophobia). These signs are usually followed by blind spots in the central field of vision (scotomas), loss of color perception, and loss of peripheral vision. Most individuals with this condition are legally blind by mid adulthood.[2][3]

There are over 30 types of CRD caused by mutations in several different genes that can be inherited in many different ways including autosomal recessive, autosomal dominant, X-linked or mitochondrial patterns.[1] CRDs are usually non-syndromic, but they may also be part of several syndromes. There is no cure for CRD; however, there may be ways to slow the disease process. Depending on the underlying cause of CRD and other associated symptoms, research may be ongoing to try to identify an effective treatment.[3][4]
Last updated: 6/22/2017

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
80%-99% of people have these symptoms
Abnormality of retinal pigmentation 0007703
Nyctalopia
Night blindness
Night-blindness
Poor night vision
[ more ] 		0000662
Photophobia
Extreme sensitivity of the eyes to light
Light hypersensitivity
[ more ] 		0000613
30%-79% of people have these symptoms
Color vision defect
Abnormal color vision
Abnormality of color vision
[ more ] 		0000551
5%-29% of people have these symptoms
Visual impairment
Impaired vision
Loss of eyesight
Poor vision
[ more ] 		0000505
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Last updated: 7/1/2020
Currently, there is no treatment to stop a person with cone-rod dystrophy (CRD) from losing their vision. However, there may be treatment options that can help slow down the degenerative process, such as light avoidance and the use of low-vision aids. It is important that people with CRD receive support and resources to help them cope with the social and psychological impact of vision loss.[3]

Possible future treatments for CRD may include: gene therapy, stem cell therapy, and retinal implants.[4][5] Many of these therapies are still being tested in animal models of CRD.[6] Before being approved as a treatment that will be available outside of research, a therapy must be found to be both effective and safe in people with CRD through research clinical trials.
Last updated: 6/22/2017

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnosis includes other hereditary cone disorders (including achrompatopsia and allied cone dysfunction syndromes, cone dystrophy and Stargardt disease) and the rod-cone dystrophy, also known asretinitis pigmentosa, which is distinguished by the sequence of photoreceptor involvement (rod photoreceptors followed by cone photoreceptors).
Visit the Orphanet disease page for more information.

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

  • ClinicalTrials.gov lists trials that are related to Cone-rod dystrophy. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.
  • The U.S. National Institutes of Health, through the National Library of Medicine, developed ClinicalTrials.gov to provide patients, family members, and members of the public with current information on clinical research studies. There is a study titled Screening Study for the Evaluation and Diagnosis of Potential Research Participants which may be of interest to you.

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.

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.
  • 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-rod dystrophy. Click on the link to view a sample search on this topic.

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. Heckenlively J. Cone Dystrophy. NORD. 2010; https://rarediseases.org/rare-diseases/cone-dystrophy/.
  2. cone-rod dystrophy. Genetics Home Reference. February 2016; https://ghr.nlm.nih.gov/condition/cone-rod-dystrophy.
  3. Hamel C. Cone rod dystrophy. Orphanet. February 2007; http://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=1872.
  4. Sahel JA, Marazova K, Audo I. Clinical characteristics and current therapies for inherited retinal degenerations. Cold Spring Harb Perspect Med. Oct 16, 2014; 5(2):http://www.ncbi.nlm.nih.gov/pubmed/25324231.
  5. Benjamin M. Nash, Dale C. Wright, John R. Grigg, Bruce Bennetts, Robyn V. Jamieson. Retinal dystrophies, genomic applications in diagnosis and prospects for therapy. Translational Pediatrics. April 2015; 4(2):139-163. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4729094/.
  6. Santos-Ferreira T, Völkner M, Borsch O, et al. Stem Cell-Derived Photoreceptor Transplants Differentially Integrate Into Mouse Models of Cone-Rod Dystrophy. Invest Ophthalmol Vis Sci. June 1 2016; 57(7):3509-20. https://www.ncbi.nlm.nih.gov/pubmed/27367586.