Choroideremia (/kɒˌrɔɪdɪˈriːmiə/; CHM) is a rare, X-linked recessive form of hereditary retinal degeneration that affects roughly 1 in 50,000 males.

Progression continues throughout the individual's life, but both the rate of change and the degree of visual loss are variable among those affected, even within the same family.

While the complete mechanism of disease is not fully understood, the lack of a functional protein in the retina results in cell death and the gradual deterioration of the retinal pigment epithelium (RPE), photoreceptors and the choroid.

[8] Individuals with choroideremia tend to maintain good visual acuity into their 40s, but eventually lose all sight at some point in the 50–70 age range.

The same study found the mean rate of visual acuity loss to be about 0.09 logMAR per 5 years, which is roughly 1 row on a Snellen chart.

[8] Gene therapy is currently not a treatment option, however human clinical trials for both choroideremia and Leber's congenital amaurosis (LCA) have produced somewhat promising results.

In 2016, researchers were optimistic that the positive results of 32 choroideremia patients treated over four and a half years with gene therapy in four countries could be long-lasting.

[23] For women who carry a mutation in the CHM gene, preimplantation genetic diagnosis can be used during the in-vitro fertilization process to select unaffected embryos to implant.

The study found "no evidence of adverse proliferation, rejection, or serious ocular or systemic safety issues related to the transplanted tissue.

"[25][26] A 2015 study used CRISPR/Cas9 to repair mutations in patient-derived induced pluripotent stem cells that cause X-linked retinitis pigmentosa.

[9] Initially, the condition was thought to be a developmental disorder which caused the absence of a majority of the choroid (hence the probable use of the ancient Greek suffix “eremia,” meaning barren land or desert).

[29] In many inherited retinal diseases the protein affected by the mutation is directly involved in the light sensing function of the eye, however this is not the case in choroideremia.