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Disease Profile

Cone-rod dystrophy

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.
1-9 / 100 000

3,310 - 29,790

US Estimated

1-9 / 100 000

5,135 - 46,215

Europe Estimated

Age of onset

Adolescent

ICD-10

H35.5

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.

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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Categories

Congenital and Genetic Diseases; Eye diseases

Summary

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]

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
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

Treatment

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 therapystem 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.

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 Supporting this Disease

    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.
        • 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.

          References

          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; https://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):https://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. https://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.

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