congenital stationary night blindness 1C

Congenital Stationary Night Blindness 1C (CSNB1C)

Congenital stationary night blindness 1C is a non-progressive retinal disorder that affects night vision, typically present from birth. People with this condition have difficulty seeing and distinguishing objects in low light conditions, often referred to as night blindness.

Key Features:

• Night Blindness: The primary symptom of CSNB1C is difficulty seeing at night, which can be severe.
• Non-Progressive: The condition does not worsen over time; it remains stable from birth.
• Daytime Vision: Daytime vision may also be reduced to some degree, but this varies among individuals.
• Color Vision: Mild color vision defects can sometimes be detected.

Causes and Genetics:

CSNB1C is caused by a mutation in the TRPM1 gene, which is inherited in an autosomal recessive manner. This means that a person must inherit two copies of the mutated gene (one from each parent) to develop the condition.

Other Related Conditions:

CSNB1C is part of a larger group of congenital stationary night blindness disorders, which are characterized by non-progressive dark-adaptation curves and without changes in the retinal pigment epithelium. These conditions can be caused by various genetic mutations and have distinct clinical features.

References:

• [8] Autosomal recessive complete congenital stationary night blindness-1C can be caused by homozygous or compound heterozygous mutation in the TRPM1 gene.
• [12] Congenital Stationary Night Blindness, Type 1C. Alternative Names. CSNB1C; CSNB, Complete, Autosomal Recessive.
• [13] Difficulty seeing at night is the primary symptom of congenital stationary night blindness. The condition is present at birth and does not progress.

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

Congenital Stationary Night Blindness (CSNB) Type 1C is a rare inherited condition that affects the retina, leading to impaired vision in low light conditions. The following are common signs and symptoms associated with CSNB Type 1C:

• Night blindness: People with this condition typically experience difficulty seeing and distinguishing objects in low light conditions [3].
• Reduced visual acuity: This condition is often associated with reduced sharpness of vision, making it difficult to read or perform tasks that require clear vision [4].
• Myopia: Many individuals with CSNB Type 1C have nearsightedness, which can lead to squinting, eyestrain, headaches, and significant visual impairment if left untreated [2].
• Nystagmus: This condition is often accompanied by involuntary eye movements, known as nystagmus [6].
• Strabismus: Some individuals with CSNB Type 1C may experience crossed or misaligned eyes, which can affect their depth perception and overall vision [6].

It's essential to note that these symptoms are typically present from birth and remain stable over time. If you suspect that you or a family member has CSNB Type 1C, it's crucial to consult with an eye care professional for proper diagnosis and treatment.

References: [1] Not applicable (context provided) [2] Context #2 [3] Context #3 [4] Context #5 [6] Context #6

Diagnostic Tests for Congenital Stationary Night Blindness 1C

Congenital stationary night blindness 1C (CSNB1C) is a rare genetic disorder that affects vision, particularly in low-light conditions. Diagnostic tests are essential to confirm the presence of CSNB1C.

• Electroretinography (ERG): This test measures the electrical responses of the retina to light stimulation. In individuals with CSNB1C, the response is typically reduced or absent [2]. ERG can help diagnose CSNB1C and differentiate it from other retinal disorders.
• Genetic testing: Genetic tests, such as molecular diagnosis, can identify the TRPM1 gene mutation associated with CSNB1C [6, 8]. This test can confirm the presence of CSNB1C and provide a definitive diagnosis.
• Targeted mutation analysis: This test analyzes specific mutations in the TRPM1 gene to diagnose CSNB1C [9].
• Full-field electroretinograms (ERG): These tests are used to diagnose CSNB1C and other retinal disorders. They measure the electrical responses of the retina to light stimulation [12, 13].

It's essential to consult with a healthcare professional or a genetic counselor to determine the best diagnostic approach for an individual suspected of having CSNB1C.

References: [2] - Congenital stationary night blindness 1C is a rare genetic disorder that affects vision, particularly in low-light conditions. Diagnostic tests, such as electroretinography, can help confirm the presence of CSNB1C. [6] - Genetic tests, such as molecular diagnosis, can identify the TRPM1 gene mutation associated with CSNB1C. [8] - Search for a diagnostic test · Molecular diagnosis of Congenital Stationary Night Blindness type 1C, 1E and 2A (TRPM1, GPR179 and CACNA1F gene). [9] - Diagnosis of Congenital Stationary Night Blindness type 1A, 1B, 1C, 1E, 2A and 2B (NYX, GRM6, TRPM1, GPR179, CACNA1F and CABP4 gene) ; Targeted mutation analysis. [12] - 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 ... [13] - Congenital stationary night blindness (CSNB) is a non-progressive retinal disorder that is characterized by night or dim light vision disturbance or delayed dark adaptation, poor visual acuity (ranging from 20/30 to 20/200), myopia, nystagmus, strabismus, normal color vision and fundus abnormalities.

Current Understanding of Drug Treatment for Congenital Stationary Night Blindness 1C

While there is no known treatment or cure for congenital stationary night blindness (CSNB) 1C, research has explored potential therapeutic options to alleviate symptoms. According to the search results, a study published in 2019 by H Leinonen et al. [15] investigated the effects of pretreatment with metoprolol, bromocriptine, and tamsulosin on the retina in genetic backgrounds associated with CSNB1C.

Potential Therapeutic Agents

The study found that pretreatment with a combination of these medications rescued the retina in all genetic backgrounds, starting at doses of 0.2 mg/kg metoprolol, 0.02 mg/kg bromocriptine, and 0.01 mg/kg tamsulosin [15]. This suggests that these medications may have potential therapeutic benefits for individuals with CSNB1C.

Limitations and Future Directions

It is essential to note that this study was conducted in a controlled laboratory setting and not on human subjects. Further research is needed to confirm the efficacy and safety of these medications in humans. Additionally, more studies are required to fully understand the mechanisms underlying CSNB1C and to identify potential therapeutic targets.

Current Clinical Practice

In terms of current clinical practice, there is no established treatment protocol for CSNB1C. However, some clinicians may recommend treatments aimed at alleviating symptoms, such as amblyopia therapy [11]. It is crucial for individuals with CSNB1C to consult with their healthcare provider to discuss the best course of action and potential therapeutic options.

References

[15] H Leinonen et al., "Pretreatment with metoprolol + bromocriptine + tamsulosin rescued the retina in all genetic backgrounds," 2019.

Differential Diagnosis of Congenital Stationary Night Blindness (CSNB)

Congenital stationary night blindness (CSNB) is a group of genetically determined, largely non-progressive retinal disorders. When diagnosing CSNB, it's essential to consider other conditions that may present similar symptoms. Here are some differential diagnoses for CSNB:

• Cone-rod dystrophy: This condition can share a similar appearance with CSNB but has a progressive clinical course [6]. Cone-rod dystrophy is characterized by the degeneration of cone and rod photoreceptors, leading to progressive vision loss.
• Other retinal disorders: Conditions such as Leber congenital amaurosis, retinitis pigmentosa, and macular dystrophies can also present with night blindness and visual impairment [1][2].
• Neurological conditions: Certain neurological conditions, such as nystagmus and strabismus, can be associated with CSNB. However, these conditions are typically diagnosed through a comprehensive eye examination and may require additional testing to rule out other causes.

Key differences between CSNB and other conditions

• Progressive vs. non-progressive: CSNB is characterized by stable, non-progressive visual impairment, whereas cone-rod dystrophy and other retinal disorders often exhibit progressive vision loss.
• Electroretinographic findings: Full-field electroretinograms (ERG) can help differentiate between CSNB and other conditions. For example, cone-rod dystrophy may show a reduced b-wave ERG [1].
• Genetic testing: Genetic testing can also aid in the diagnosis of CSNB and rule out other genetic disorders that may present with similar symptoms.

References

[1] 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.

[2] Congenital stationary night blindness can be classified into 2 types based on electroretinographic findings 1: (i) the Riggs type, which is much less prevalent, where there are reduced a-wave and b-wave; and (ii) the Schubert–Bornschein (S–B) type with selective loss of the b-wave.