Oguchi disease-2

Oguchi Disease-2 Description

Oguchi disease-2, also known as GRK1 Oguchi disease or CSNBO2, is a rare autosomal recessive form of congenital stationary night blindness. This condition affects the retina and impairs night vision, but does not progress over time.

• Visual Functions Affected: Visual functions such as acuity, field, and color vision are typically unaffected in individuals with Oguchi disease-2.
• Characteristics: The condition is characterized by impaired night vision, often associated with nystagmus (involuntary eye movements) and myopia (nearsightedness).
• Genetic Cause: Oguchi disease-2 is caused by mutations in the GRK1 gene, which plays a crucial role in regulating visual function.

According to search results [5], Oguchi disease-2 is a rare autosomal recessive form of congenital stationary night blindness. This condition affects the retina and impairs night vision, but does not progress over time.

References:

[4] - Description of Oguchi disease as a rare autosomal recessive form of congenital stationary night blindness in which all other visual functions are unaffected. [5] - Definition of Oguchi disease-2 as a rare autosomal recessive form of congenital stationary night blindness with impaired night vision and unaffected visual acuity, field, and color vision.

Signs and Symptoms of Oguchi Disease

Oguchi disease, also known as congenital stationary night blindness (CSNB), is a rare autosomal recessive disorder that primarily affects night vision. The symptoms of Oguchi disease can vary from person to person, but here are some common signs and symptoms associated with this condition:

• Night Blindness: Patients with Oguchi disease often complain of static nyctalopia since childhood, which means they have difficulty seeing in low light conditions.
• Fundus Discoloration: A distinctive feature of Oguchi disease is a golden or gray-white discoloration of the fundus that disappears in the dark-adapted state and reappears shortly after exposure to light. This phenomenon is known as the Mizuo-Nakamura effect [8].
• Normal Daytime Vision: Despite the night blindness, patients with Oguchi disease have normal daytime vision, color vision, and side vision.
• No Progression of Symptoms: Oguchi disease is a nonprogressive disorder, meaning that the symptoms do not worsen over time.

It's essential to note that these symptoms can be subjective and may not be immediately apparent. A comprehensive eye examination by an ophthalmologist is necessary for an accurate diagnosis.

References:

• [2] - Oguchi's disease is a rare form of congenital stationary night blindness, associated with light-dependent golden fundus discoloration.
• [3] - Oguchi disease is a rare autosomal recessive stationary night blindness with a greyish or green-yellow discoloration of the fundus at the posterior pole.
• [10] - Patients with CSNB may complain of poor night or dim-light vision. Those with Oguchi disease demonstrate the Mizuo-Nakamura phenomenon in which the fundus is unremarkable in the dark-adapted state but has a yellow color in lighted conditions.
• [11] - Oguchi disease is a nonprogressive disorder that causes night blindness. It is present at birth. Daytime vision, color vision, and side vision are all normal.

Diagnostic Tests for Oguchi Disease-2

Oguchi disease-2, also known as congenital stationary night blindness, can be diagnosed through various tests that assess the retina and its function.

• Electrophysiologic testing: This test measures the electrical activity of the retina in response to light. In individuals with Oguchi disease-2, the a-wave on single flash electroretinograms (ERG) is decreased or absent under lighted conditions but increases after prolonged dark adaptation [7].
• Fluorescein angiogram: This test involves injecting a fluorescent dye into the bloodstream and taking photographs of the retina as the dye flows through it. In individuals with Oguchi disease-2, the fluorescein angiogram is normal [8].
• Genetic testing: Molecular diagnosis of Oguchi Disease type 1 and 2 (SAG and GRK1 gene) can be performed using Next-Generation Sequencing (NGS) or other genetic testing methods. This test identifies mutations in the SAG or GRK1 genes, which are responsible for the condition [5].
• Clinical Genetic Test: Clinical genetic tests offered by Intergen and CGC Genetics for conditions (1): Oguchi disease-2; Testing genes (1): GRK1 (13q34) can also be used to diagnose this condition. These tests use various methodologies, including Next-Generation Sequencing or Bi-directional sequencing [6][9].

These diagnostic tests are essential in confirming the diagnosis of Oguchi disease-2 and distinguishing it from other retinal disorders.

References:

[5] Molecular diagnosis of Oguchi Disease type 1 and 2 (SAG and GRK1 gene) [6] Clinical Genetic Test offered by Intergen for conditions (1): Oguchi disease-2; Testing genes (1): GRK1 (13q34) [7] The A- and b-waves on single flash electroretinograms (ERG) are decreased or absent under lighted conditions but increases after prolonged dark adaptation [8] Fluorescein angiogram is normal in individuals with Oguchi disease-2 [9] Clinical Genetic Test offered by CGC Genetics for conditions (1): Oguchi disease-2; Testing genes (1): GRK1 (13q34)

Current Status of Drug Treatment for Oguchi Disease

Unfortunately, there is no specific treatment available for Oguchi disease. However, research has been conducted to explore potential therapeutic options.

• Pretreatment with metoprolol + bromocriptine + tamsulosin: A study published in 2019 found that pretreatment with this combination of 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 [6].
• No specific treatment: As of now, there is no established drug treatment for Oguchi disease. Management typically involves family screening, genetic testing, and counseling due to the autosomal recessive inheritance pattern [15].

It's essential to note that these findings are based on limited research, and more studies are needed to fully understand the potential therapeutic options for Oguchi disease.

References: [6] Leinonen H et al. (2019) - Cited by 16 [15] May 31, 2021 - Thus far, no treatment for Oguchi's disease has been found.

The differential diagnosis for Oguchi disease type 2 involves conditions that can present with similar clinical findings, particularly congenital stationary night blindness and abnormal fundus changes.

According to the search results, the following conditions are considered in the differential diagnosis for Oguchi disease type 2:

• Stargardt disease [9][10]
• Female carrier of Retinitis Pigmentosa [9][13]
• Juvenile Retinoschisis [9][13]
• Progressive Cone Dystrophy [9]

These conditions can all present with abnormal fundus changes, making them potential differential diagnoses for Oguchi disease type 2. However, it's essential to note that each of these conditions has distinct clinical and genetic features that can help differentiate them from Oguchi disease.

In particular, Stargardt disease is a form of juvenile macular degeneration that typically presents with progressive vision loss and characteristic fundus changes [9]. Female carriers of Retinitis Pigmentosa may exhibit night blindness and abnormal ERG findings, but the fundus changes are often less pronounced than in Oguchi disease [13].

Juvenile Retinoschisis is a rare condition characterized by splitting of the retina's inner layers, which can lead to vision loss and abnormal fundus changes [13]. Progressive Cone Dystrophy is a form of inherited cone photoreceptor degeneration that typically presents with progressive vision loss and characteristic fundus changes [9].

To establish an accurate diagnosis, it's crucial to consider these differential diagnoses and perform comprehensive clinical evaluations, including ERG testing and genetic analysis.

References:

[9] - This condition may have fundus changes but without the classical ... [10] CSNB with abnormal fundi includes