Short answer · Medically reviewed summary · Last updated: 2026-05-08
Choroideremia is a rare, X-linked genetic disorder caused by mutations in the CHM gene, which leads to the progressive degeneration of the choroid, retinal pigment epithelium, and photoreceptor cells. Because it is inherited in an X-linked recessive pattern, it primarily affects males, causing a gradual loss of vision that typically begins with night blindness in childhood or adolescence. What causes Choroideremia at the genetic level? The primary cause of Choroideremia is a mutation in the CHM gene, located on the X chromosome.
Which are the causes of Choroideremia?
Causes of Choroideremia explained: genetic and environmental factors, reviewed against medical sources, plus patient perspectives.
Choroideremia is a rare, X-linked genetic disorder caused by mutations in the CHM gene, which leads to the progressive degeneration of the choroid, retinal pigment epithelium, and photoreceptor cells. Because it is inherited in an X-linked recessive pattern, it primarily affects males, causing a gradual loss of vision that typically begins with night blindness in childhood or adolescence.
What causes Choroideremia at the genetic level?
The primary cause of Choroideremia is a mutation in the CHM gene, located on the X chromosome. This gene provides instructions for producing a protein called Rab escort protein-1 (REP-1). REP-1 is essential for intracellular protein trafficking; without functional REP-1, cells in the retina cannot properly manage the transport of proteins, leading to the premature death of light-sensing cells. In our DiseaseMaps community, 96 members have shared their experiences, highlighting the unique genetic journey of those living with this condition.
Is Choroideremia hereditary?
Yes, Choroideremia is strictly an inherited condition. Because the CHM gene is located on the X chromosome, the inheritance follows an X-linked recessive pattern:
- Males: Only one altered copy of the gene is sufficient to cause the disease, as they have only one X chromosome.
- Females: Usually carry the mutation on one X chromosome and are typically asymptomatic carriers, though they may experience mild, late-onset vision changes.
- Transmission: An affected male will pass the mutation to all of his daughters but none of his sons.
Are there environmental or external triggers?
There are no known environmental, dietary, or lifestyle triggers for Choroideremia. Unlike some complex diseases, this condition is purely genetic. It is not caused by autoimmune reactions, infections, or metabolic imbalances, meaning that lifestyle changes cannot prevent the progression of Choroideremia.
What is the current state of research into the etiology?
While the genetic cause of Choroideremia is well-understood, researchers are actively investigating ways to bypass the lack of functional REP-1. Current clinical research is heavily focused on gene therapy, which aims to introduce a healthy copy of the CHM gene into the retinal cells to restore normal protein trafficking and slow or halt the progression of Choroideremia.
Next steps
- Consult with a retina specialist or an ophthalmologist for a baseline electroretinogram (ERG) and visual field test.
- Seek a referral to a clinical geneticist to confirm the CHM mutation and discuss family planning.
- Join the DiseaseMaps community to connect with other families navigating this diagnosis.
- Monitor clinical trial databases like ClinicalTrials.gov for the latest gene therapy research.
Medical disclaimer: This information is for educational purposes only and should not replace professional medical advice, diagnosis, or treatment.
References
- NIH Genetic and Rare Diseases Information Center (GARD): Choroideremia.
- Orphanet: Choroideremia (ORPHA:166).
- OMIM (Online Mendelian Inheritance in Man): Choroideremia; CHM.
- Choroideremia Research Foundation (CRF).
