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Gene therapy development for choroideremia in Russia
Important update Important update

Development of a choroideremia gene therapy program has started in Russia

RetinaFond, together with Sechenov University, has started developing a domestic gene therapy candidate for choroideremia.

What is choroideremia?

Choroideremia (CHM) is a rare inherited retinal disease that causes progressive vision loss. It is caused by a mutation in the CHM gene on the X chromosome.

The disease gradually affects three key retinal structures: the choroid, the retinal pigment epithelium (RPE), and the photoreceptors.

The first symptoms usually appear in childhood as night blindness (nyctalopia) — difficulty orienting in dim light or darkness. Over time, progressive narrowing of peripheral visual fields leads to “tunnel vision,” where only a small area of central vision remains.

Key facts:

  • ✓ Estimated prevalence is approximately 1 in 50,000 people
  • ✓ X-linked recessive inheritance — the disease predominantly affects males
  • ✓ Female carriers usually have no vision problems, although in rare cases varying degrees of impairment may occur
  • ✓ International clinical trials of CHM gene therapy are actively underway

Main symptoms

What happens to vision in choroideremia

Night blindness

Night blindness

Worsening vision in dim light and slow eye adaptation when moving from bright light into darkness

Tunnel vision

Tunnel vision

Gradual narrowing of peripheral (side) vision, leaving only a small area of central vision

Progressive course

Progressive course

Gradual vision loss over decades. The pace of change is strictly individual

How is CHM inherited?

Choroideremia is inherited in an X-linked recessive pattern. This means the gene with the mutation is on the X chromosome. This determines very different disease courses in males and females.

Males

Males have only one X chromosome. If they inherit the X chromosome with a CHM mutation, the disease always develops, because they do not have a second “healthy” X chromosome to compensate for the defect.

Females

Females have two X chromosomes. If the mutation is present in only one of them, the woman becomes a carrier. The second (healthy) chromosome often compensates for the defect, so the disease frequently runs its course without symptoms. However, some female carriers may experience noticeable vision impairment.

X-linked recessive inheritance pattern

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