retinitis pigmentosa 27

Retinitis Pigmentosa (RP): A Group of Inherited Eye Diseases

Retinitis pigmentosa (RP) is a group of inherited eye diseases that cause progressive vision loss. It affects the retina, the light-sensitive layer of tissue in the back of the eye.

• Causes: RP is caused by genetic variants that affect the retina's ability to function properly.
• Symptoms:
  • Poor vision in dim light
  • Constriction in the visual field (peripheral vision)
  • Tunnel vision as peripheral vision worsens
  • Complete blindness is uncommon, but can occur in advanced cases
• Inheritance: RP often has an autosomal dominant inheritance pattern, meaning one copy of an altered gene in each cell is sufficient to cause the disorder.
• Prevalence: The condition affects approximately 1 in 4,000 people worldwide.

Key Facts

• RP is a progressive degeneration that starts with involvement of the rod photoreceptors, followed by cone photoreceptors.
• Symptoms usually start in childhood or adolescence.
• RP is a genetic disease that people are born with.
• The condition can lead to complete blindness in advanced cases.

References:

[12] - Estimated prevalence of RP worldwide [14] - Description of symptoms and inheritance pattern [5] - Initial symptoms of RP, including poor vision in dim light [6] - Inheritance pattern and prevalence of autosomal dominant RP

Common Signs and Symptoms of Retinitis Pigmentosa

Retinitis pigmentosa (RP) is a group of rare, genetic disorders that affect the retina's ability to respond to light. The symptoms of RP can vary from person to person, but there are some common signs and symptoms that are often associated with this condition.

• Night Blindness: One of the earliest and most common symptoms of RP is night blindness, which makes it difficult for individuals to see in low-light conditions [1][2]. This is because the retina's ability to adapt to dim light is impaired.
• Peripheral Vision Loss: As RP progresses, people may experience a gradual loss of peripheral (side) vision, often described as "tunnel vision" [3][4]. This can make it difficult to see objects or people outside of their direct line of sight.
• Reduced Vision in Poor Lighting: Individuals with RP may also have difficulty seeing in poor lighting conditions, such as shadows or dimly lit rooms [5].
• Blind Spots: Some people with RP may experience blind spots in their peripheral vision, which can be a sign of the condition's progression [6].

It's essential to note that these symptoms can vary in severity and may not necessarily progress at the same rate for everyone. If you're experiencing any of these symptoms, it's crucial to consult with an eye care professional for proper diagnosis and treatment.

References: [1] - Search result 1: "Problems with night vision." [2] - Search result 6: "The first sign of retinitis pigmentosa is usually a loss of night vision..." [3] - Search result 7: "Early symptoms of retinitis pigmentosa include defective night vision and peripheral vision." [4] - Search result 11: "Signs and symptoms of RP may include loss of night vision (night blindness), gradual loss of side (peripheral) vision..." [5] - Search result 3: "Reduced vision in poor lighting or dark conditions, or in shadows" [6] - Search result 4: "Blind spots in peripheral (side) vision"

Diagnostic Tests for Retinitis Pigmentosa

Retinitis pigmentosa (RP) is a group of inherited eye diseases that affect the retina, and diagnostic tests play a crucial role in its diagnosis. Here are some common diagnostic tests used to investigate RP:

• Electro-diagnostic tests: These tests include electroretinogram (ERG), electro-oculogram (EOG), and multifocal electroretinogram (mfERG). They provide an objective measure of rod and cone function across the retina [3].
• Genetic testing: This test looks at a sample of your blood or other tissues to see if you have certain genes that are associated with RP. Genetic testing can identify specific genetic mutations that cause RP, such as the RPE65 gene mutation [4].
• Electroretinogram (ERG): ERG is the most critical diagnostic test for RP because it provides an objective measure of rod and cone function across the retina [3]. It helps confirm the diagnosis by demonstrating attenuated rod and cone signals [8].
• Optical Coherence Tomography (OCT) scan: An OCT scan can show loss of photoreceptors in the retina, which is a common finding in RP patients [6].

These diagnostic tests help healthcare professionals diagnose RP and determine its severity. Early diagnosis and genetic testing can also provide valuable information for family planning and genetic counseling.

References: [3] May 16, 2024 — Electroretinogram. [4] Nov 11, 2024 — Genetic testing. [6] The diagnosis of RP is based on peripheral visual field loss, pigment deposits in fundus, loss of photoreceptors at the optical coherence tomography (OCT) scan ... [8] Sep 21, 2023 — Electroretinograms help confirm the diagnosis by demonstrating attenuated rod and cone signals.

Current Drug Treatments for Retinitis Pigmentosa

While there are no curative treatments available for retinitis pigmentosa (RP), several medications have shown promise in slowing down the progression of the disease or improving visual function. Here are some of the current drug treatments being explored:

• Luxturna: This is a gene therapy product approved by the FDA to treat a specific type of RP caused by mutations in the RPE65 gene. It works by delivering a healthy copy of the RPE65 gene to retinal cells, allowing them to produce a healthier version of the protein.
• QR-421a: This is an experimental therapy that has shown promise in improving visual function in patients with RP. It involves injecting a healthy version of the USH2A protein into the retina, which helps to slow down the progression of the disease.
• Acetazolamide: Studies have shown that oral acetazolamide can improve visual function in some patients with RP. This medication works by reducing fluid buildup in the retina and improving retinal function.

Emerging Therapies

Researchers are also exploring new therapies to treat RP, including:

• N-acetylcysteine (NAC): A Phase 3 clinical trial is currently underway at Johns Hopkins University to investigate the use of NAC for treating RP.
• Gene therapy: New research suggests that a type of gene therapy can improve vision in people who have lost nearly all sight to RP.

Other Treatments

In addition to these medications, some patients with RP may also benefit from:

• Vitamins and supplements: Certain vitamins and supplements, such as vitamin A, E, and C, may help to slow down the progression of RP.
• Lifestyle modifications: Making healthy lifestyle choices, such as eating a balanced diet and exercising regularly, can also help to manage symptoms of RP.

It's essential to note that these treatments are not curative and may have varying degrees of success. Patients with RP should consult with their healthcare provider to discuss the best treatment options for their individual needs.

References:

• [1] by N Cross · 2022 · Cited by 37 — Currently, Luxturna® (voretigene neparvovec) is the only approved therapy for RP and is only authorised for the treatment of a small sub-...
• [4] by KY Wu · 2023 · Cited by 49 — These therapies aim to target the underlying genetic cause of the disease and offer the potential to stop the progression of RP, offering a cure for some...
• [5] May 16, 2024 — Of the many therapies tried, oral acetazolamide has shown the most encouraging results with some improvement in visual function. Studies by...
• [9] Oct 20, 2024 — New research suggests that a new kind of gene therapy can improve vision in people who have lost nearly all sight to retinitis pigmentosa.
• [7] Oct 7, 2024 — Johns Hopkins University (JHU) has launched a Phase 3 clinical trial of N-acetylcysteine (NAC) for the treatment of retinitis pigmentosa (RP).

Differential Diagnoses for Retinitis Pigmentosa

Retinitis pigmentosa (RP) is a rare genetic disorder that affects the retina, leading to progressive vision loss. However, there are several other conditions that can mimic the symptoms of RP, making differential diagnosis crucial for accurate treatment and management.

Here are some of the key differential diagnoses for retinitis pigmentosa:

• Traumatic retinopathy: This condition occurs when the retina is damaged due to trauma or injury, leading to similar symptoms as RP.
• Retinal inflammatory diseases: Conditions such as uveitis, retinal vasculitis, and retinal detachment can cause inflammation in the retina, which may be mistaken for RP.
• Autoimmune paraneoplastic retinopathy: This is a rare condition where an autoimmune response to cancer causes damage to the retina, leading to symptoms similar to RP.
• Drug-induced retinal toxicity: Certain medications, such as chloroquine and hydroxychloroquine, can cause retinal toxicity, which may be mistaken for RP.

Key Diagnostic Features

To differentiate these conditions from RP, clinicians should look out for the following key features:

• Unilateral vs. bilateral involvement: Traumatic retinopathy and autoimmune paraneoplastic retinopathy often present with unilateral involvement, whereas RP typically affects both eyes.
• Presence of inflammation: Retinal inflammatory diseases are characterized by signs of inflammation in the retina, such as vitreous haze or retinal vasculitis.
• History of trauma or cancer: A history of trauma or cancer can suggest traumatic retinopathy or autoimmune paraneoplastic retinopathy, respectively.

Diagnostic Tests

The following diagnostic tests may be used to differentiate these conditions from RP:

• Dilated eye examination with visual field test
• Electroretinography (ERG) test
• Optical coherence tomography (OCT) scan
• Genetic testing: This can help identify genetic mutations associated with RP and rule out other conditions.

References

1. [4] Clinical diagnosis is based on the presence of night blindness and peripheral visual field defects, lesions in the fundus, hypovolted ...
2. [7] Aug 29, 2024 — Genetic testing · DIFFERENTIAL DIAGNOSIS · Traumatic retinopathy · Retinal inflammatory diseases · Autoimmune paraneoplastic retinopathy · Drug ...
3. [8] May 8, 2008 — Differential Diagnoses for Unilateral Retinitis Pigmentosa (see Discussion above) · Prior trauma · Retained metallic intraocular foreign body ...