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congenital stationary night blindness 1A

Description

Congenital Stationary Night Blindness (CSNB) Type 1A: A Rare Genetic Disorder

Congenital stationary night blindness type 1A, also known as CSNB1A, is a rare genetic disorder that affects the retina and impairs night vision. It is an X-linked disorder, meaning it is inherited in an X-linked recessive pattern, where only males are affected and carrier females do not have clinical disease.

Key Features:

  • Impaired Night Vision: Individuals with CSNB1A experience difficulty seeing in low light conditions.
  • Reduced Visual Acuity: Affected individuals may have reduced visual acuity, ranging from 20/30 to 20/200.
  • Defective Dark Adaptation: People with CSNB1A may take longer than usual to adapt to changes in lighting conditions.
  • Refractive Error: Myopia (nearsightedness) is a common refractive error associated with CSNB1A, ranging from low to high degrees.

Other Symptoms:

  • Nystagmus (involuntary eye movements)
  • Strabismus (crossed eyes)
  • Normal color vision

Genetic Cause: CSNB1A is caused by a mutation in the NYX gene located at Xp11.4. This genetic defect affects the retina's ability to detect light and color.

References:

[12] Congenital stationary night blindness type 1A is an X-linked disorder caused by a mutation in the NYX gene located at Xp11.4. [10] Description. Congenital stationary night blindness (CSNB) is a clinically and genetically heterogeneous group of nonprogressive retinal disorders that can be characterized by impaired night vision, decreased visual acuity, nystagmus, myopia, and strabismus. [14] X-linked congenital stationary night blindness (CSNB) is characterized by non-progressive retinal findings of reduced visual acuity ranging from 20/30 to 20/200; defective dark adaptation; refractive error, most typically myopia ranging from low (-0.25 diopters [D] to -4.75 D) to high (≥-10.00 D) but occasionally hyperopia; nystagmus; strabismus; normal color vision; and normal fundus ...

Additional Characteristics

  • Nystagmus
  • Strabismus
  • Reduced Visual Acuity
  • Normal Color Vision
  • Impaired Night Vision
  • Defective Dark Adaptation
  • Refractive Error (Myopia)

Signs and Symptoms

Common Signs and Symptoms of Congenital Stationary Night Blindness (CSNB) Type 1A

Congenital stationary night blindness is a rare, inherited eye condition that primarily affects people assigned male at birth. The signs and symptoms of CSNB Type 1A can vary from person to person but often include:

  • Night Blindness: This is the most common symptom of CSNB Type 1A, where individuals have difficulty seeing in low light conditions from early childhood [5].
  • Visual Acuity: Mild to moderate reduction in visual acuity is a characteristic feature of CSNB Type 1A. People with this condition may experience blurred vision or difficulty reading and writing [7].
  • Fundus Appearance: The fundus, which is the innermost layer of the eye, appears normal in individuals with CSNB Type 1A, except for myopic changes that are commonly found [2].

In addition to these symptoms, people with CSNB Type 1A may also experience other vision problems, including:

  • Increased Sensitivity to Light (Photophobia): Some individuals with CSNB Type 1A may be sensitive to light and experience discomfort or pain when exposed to bright lights.
  • Loss of Sharpness (Reduced Visual Acuity): People with this condition may have difficulty seeing sharp images or experiencing reduced visual acuity in general.

It's essential to note that the symptoms of CSNB Type 1A can vary from person to person, and not everyone will experience all of these signs. If you suspect that you or someone else has CSNB Type 1A, it's crucial to consult with an eye care professional for a proper diagnosis and treatment plan.

References: [1] - [9] are citations from the search results provided in the context block above.

Additional Symptoms

  • Night Blindness
  • Increased Sensitivity to Light (Photophobia)
  • Loss of Sharpness (Reduced Visual Acuity)
  • Visual Acuity (mild to moderate reduction)
  • Fundus Appearance (normal with myopic changes)

Diagnostic Tests

Diagnostic Tests for Congenital Stationary Night Blindness (CSNB) Type 1A

Congenital stationary night blindness type 1A is an X-linked disorder caused by a mutation in the NYX gene. Diagnosing this condition typically involves a combination of clinical evaluation, genetic testing, and specialized tests to assess retinal function.

  • Electroretinography (ERG): This test measures the electrical activity of the retina in response to light stimuli. In CSNB type 1A, ERG results show reduced or absent b-waves, indicating dysfunction of the rod photoreceptors [3][4].
  • Genetic testing: Molecular genetic analysis can confirm the presence of a mutation in the NYX gene, which is responsible for CSNB type 1A. This test is particularly useful for confirming the diagnosis in affected males and carrier females [14].
  • Clinical evaluation: A comprehensive eye examination by an ophthalmologist or optometrist is essential to rule out other conditions that may cause similar symptoms. The clinical features of CSNB type 1A include night blindness, reduced visual acuity, and severe nearsightedness (high myopia) [13].

Other diagnostic tests

While not specifically mentioned in the context provided, other tests like full-field ERG and dark-adapted ERG may also be used to assess retinal function in CSNB type 1A. However, these tests are more commonly associated with diagnosing other types of congenital stationary night blindness.

References:

[3] Congenital stationary night blindness (CSNB) is a group of genetically determined, largely non-progressive retinal disorders characterised by rod system dysfunction. This condition presents significant clinical and genetic heterogeneity as there are 4 types. 1,2 Diagnosis relies on full-field electroretinograms (ERG) and genetic testing to confirm the diagnosis.

[4] The Riggs type of CSNB is much less prevalent, where there are reduced a- and b-waves in response to a scotopic bright flash; and the Schubert–Bornschein (S–B) type with selective loss of the b-wave. 2–4 The Riggs type of CSNB is associated with mutations in the NYX gene.

[13] From MedlinePlus Genetics X-linked congenital stationary night blindness is a disorder of the retina, which is the specialized tissue at the back of the eye that detects light and color. People with this condition typically have difficulty seeing in low light (night blindness). They also have other vision problems, including loss of sharpness (reduced acuity), severe nearsightedness (high myopia).

[14] Congenital stationary night blindness type 1A is an X-linked disorder caused by a mutation in the NYX gene located at Xp11.4. Only males are affected and carrier females do not have clinical disease (although homozygous females with typical findings have been described).

Treatment

Based on the provided context, it appears that there is no specific drug treatment available for Congenital Stationary Night Blindness (CSNB) type 1A.

According to search result [11], CSNB type 1A is an X-linked disorder caused by a mutation in the NYX gene located at Xp11.4, and only males are affected. The treatment options mentioned are limited to correction of refractive errors, but no specific drug treatment is mentioned.

Search result [7] mentions that there is currently no treatment available for most forms of CSNB, which suggests that CSNB type 1A may not have a specific drug treatment as well.

However, it's worth noting that search result [8] mentions an FDA-approved gene therapy product (Luxturna) that has been available for treating one of the most severe Inherited Retinal Diseases (IRDs), Leber congenital amaurosis. While this is not specifically mentioned in the context of CSNB type 1A, it's possible that future research may explore similar gene therapies for other forms of IRDs, including CSNB.

In summary, based on the provided context, there does not appear to be a specific drug treatment available for Congenital Stationary Night Blindness (CSNB) type 1A. However, further research and development in the field of gene therapy may potentially lead to new treatments for this condition.

References: [7] - No treatment beyond correction of refractive errors is mentioned. [11] - Correction of refractive errors is mentioned as a treatment option, but no specific drug treatment is mentioned. [8] - FDA-approved gene therapy product (Luxturna) is mentioned for treating Leber congenital amaurosis.

Recommended Medications

  • No specific drug treatment available
  • Correction of refractive errors

💊 Drug information is sourced from ChEBI (Chemical Entities of Biological Interest) database. Always consult with a healthcare professional before starting any medication. Click on any medication name for detailed information.

Differential Diagnosis

Differential Diagnosis of Congenital Stationary Night Blindness (CSNB) Type 1A

Congenital stationary night blindness (CSNB) is a group of genetically determined, largely non-progressive retinal disorders characterized by rod system dysfunction. CSNB Type 1A is one of the four subtypes of CSNB and presents with significant clinical and genetic heterogeneity.

Key Differential Diagnoses:

  • Cone-rod dystrophy: This condition shares a similar appearance with CSNB but has a progressive clinical course. It affects both rod and cone photoreceptors, leading to progressive

Additional Differential Diagnoses

Additional Information

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