Choroideremia

Eye Deceases

Choroideremia

Choroideremia (CHM) is a rare genetic disorder of vision that often affects men.  Choroideremia causes degeneration of retina which leads to blindness. Choroideremia causes alterations in the choriocapillaris and the RPE photoreceptor complex.

Mild symptoms are observed in women carriers of this disorder. Choroideremia is an inherited X-linked disorder. A carrier male individual transmits the mutation of the gene to all his female offspring and none to the male offspring. Further female carrier of the gene has 50% chances of passing it to her offspring. If passed it the male offspring, symptomatic Choroideremia is observed. But if passed to female offspring, they just act as carriers of the gene.

ICD-10 H31.2
ICD-9 363.55
OMIM 303100
DiseasesDB 2619
MeSH D015794

Choroideremia Symptoms

Major symptoms in males comprise of gradual loss of the vision in the peripheral areas and night blindness. Night blindness is mostly the first obvious symptom and is usually seen in early childhood.
Other symptoms include reduced central vision, deafness, obesity, mental retardation, blindness and atrophy of the eye.

In females, the Choroideremia is asymptomatic and observation of fundus can show signs of Choroideremia.

Choroideremia Diagnosis & Treatment

  • Diagnosis can be prepared by observation of fundus and study of family history of patients for X-linked inheritance.
  • According to the research, mutation in the CHM gene is associated with Choroideremia.
  • No effective treatment to cure the mutation of the gene exists.

Treatment of Choroideremia

It may include some measures to relieve the symptoms as-

  • Proper proportion of dietary intake of fruits and green vegetables.
  • Daily intake of long fatty acids- Omega 3 such as docosahexaenoic acid.
  • Vitamin supplement of antioxidants.
  •  Cataract surgery, if needed.
  • Counseling for depressed patients

Some standard therapies are used to treat Choroideremia are conventional refraction and aids to improve low vision.

Choroideremia Causes

Choroideremia is a progressive degeneration of retina caused by the mutations in broadly expressed CHM gene on chromosome Xq21., This gene codes for the protein Rab escort protein (REP)-1 that is involved in the modification of lipids after translation process and successive targeting of Rab proteins present in the membrane and, GTPases that play a key role in intracellular trafficking.

Gene therapy is coming up to treat the disease.