Which are the causes of Choroideremia?

Choroideremia is a rare genetic disorder that primarily affects the eyes, specifically the retina, choroid, and retinal pigment epithelium. It is an X-linked recessive disorder, meaning that it predominantly affects males. Females can also be carriers of the condition but are usually unaffected.

The main cause of Choroideremia is a mutation in the CHM gene, which is responsible for producing a protein called Rab escort protein 1 (REP1). This protein plays a crucial role in the transportation of other proteins within cells, including those involved in the visual system. When the CHM gene is mutated, it leads to a deficiency or absence of REP1, resulting in the progressive degeneration of the retina and choroid.

The CHM gene mutation affects the functioning of specialized cells in the retina called photoreceptors. These cells are responsible for capturing light and converting it into electrical signals that are then transmitted to the brain for visual processing. In individuals with Choroideremia, the photoreceptor cells gradually deteriorate and eventually die, leading to vision loss.

Choroideremia is an inherited disorder, meaning it is passed down from parents to their children through genetic transmission. As mentioned earlier, it follows an X-linked recessive pattern, which means that the faulty gene is located on the X chromosome. Males have one X chromosome and one Y chromosome, while females have two X chromosomes. Since males have only one copy of the X chromosome, a single mutation in the CHM gene is sufficient to cause Choroideremia. In females, both copies of the gene would need to be mutated to develop the condition, making it less common in women.

It is important to note that Choroideremia is a progressive disorder, meaning that symptoms worsen over time. Initially, individuals may experience night blindness and a narrowing of their visual field. As the disease progresses, central vision becomes affected, leading to difficulties with tasks such as reading, recognizing faces, and driving. Eventually, complete blindness may occur, although the rate of progression can vary among individuals.

While there is currently no cure for Choroideremia, ongoing research is focused on developing potential treatments. Gene therapy, which involves introducing a functional copy of the CHM gene into the affected cells, shows promise in halting or slowing down the progression of the disease. Clinical trials are underway to assess the safety and efficacy of these gene therapies.

In conclusion, Choroideremia is caused by a mutation in the CHM gene, leading to a deficiency of the REP1 protein and subsequent degeneration of the retina and choroid. It is an inherited disorder that primarily affects males. The progressive nature of the disease results in vision loss over time. While there is no cure currently available, ongoing research offers hope for potential treatments in the future.