What is the official name of the CRX gene?
The official name of this gene is “cone-rod homeobox.”
CRX is the gene's official symbol. The CRX gene is also known by other names, listed below.
Read more about gene names and symbols on the About page.
What is the normal function of the CRX gene?
The CRX gene provides instructions for making a protein called the cone-rod homeobox protein. This protein is found in the eyes, specifically in the light-sensitive tissue at the back of the eye called the retina. The cone-rod homeobox protein attaches (binds) to specific regions of DNA and helps control the activity of particular genes. On the basis of this action, this protein is called a transcription factor.
In the retina, the cone-rod homeobox protein is necessary for the normal development of light-detecting cells called photoreceptors. Through its actions as a transcription factor, the cone-rod homeobox protein helps photoreceptor cells mature into two types: rods and cones. Rods are needed for vision in low light, while cones are needed for vision in bright light, including color vision. The protein also helps maintain these cells and preserve vision.
How are changes in the CRX gene related to health conditions?
- cone-rod dystrophy - caused by mutations in the CRX gene
- More than 20 mutations in the CRX gene have been found to cause cone-rod dystrophy. The problems associated with this condition include a loss of visual sharpness (acuity), an increased sensitivity to light (photophobia), and impaired color vision. These vision problems worsen over time. Cone-rod dystrophy is caused by mutations that occur in one of the two copies of theCRX gene in each cell. CRX gene mutations are responsible for about one-quarter of the cases of a form of the condition called autosomal dominant cone-rod dystrophy. These mutations lead to a reduction in the amount of functional cone-rod homeobox protein that is available to regulate other genes in the retina. As a result, maintenance of the rod and cone cells is insufficient and these cells deteriorate over time, leading to the vision problems characteristic of cone-rod dystrophy. Researchers believe that there is enough cone-rod homeobox protein function to allow for photoreceptor cell differentiation, but long-term maintenance of the cells cannot be sustained.Several CRX gene mutations have been found to cause different forms of vision loss in different individuals. It is unclear how mutations in the CRX gene can cause different eye disorders.
Genetics Home Reference provides additional information about these conditions associated with changes in the CRX gene:
Where is the CRX gene located?
Cytogenetic Location: 19q13.3
Molecular Location on chromosome 19: base pairs 47,821,842 to 47,843,330
(Homo sapiens Annotation Release 107, GRCh38.p2) (
The CRX gene is located on the long (q) arm of chromosome 19 at position 13.3.
More precisely, the CRX gene is located from base pair 47,821,842 to base pair 47,843,330 on chromosome 19.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about CRX?
You and your healthcare professional may find the following resources about CRX helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
What other names do people use for the CRX gene or gene products?
- cone-rod homeobox protein
- orthodenticle homeobox 3
See How are genetic conditions and genes named? in the Handbook.
Where can I find general information about genes?
The Handbook provides basic information about genetics in clear language.
- What is DNA?
- What is a gene?
- How do genes direct the production of proteins?
- How can gene mutations affect health and development?
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding CRX?
autosomal ; autosomal dominant ; cell ; cones ; congenital ; differentiation ; DNA ; gene ; homeobox ;photophobia ; photoreceptor ; protein ; retina ; rods ; sensitivity ; tissue ; transcription ;transcription factor
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (5 links)
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook