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Disease Profile

Oguchi disease

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

Infancy

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ICD-10

H53.6

Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Other names (AKA)

Stationary night blindness, Oguchi type

Categories

Congenital and Genetic Diseases; Eye diseases

Summary

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.
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Orpha Number: 75382

Definition
Oguchi disease is an autosomal recessive retinal disorder characterized by congenital stationary night blindness (see this term) and the Mizuo-Nakamura phenomenon.

Epidemiology
Oguchi disease is a very rare condition with approximately 50 cases described in the literature to date. It was originally discovered in Japan where the prevalence is the highest but has been found occasionally in European, American, Pakistani and Indian patients.

Clinical description
The disease is characterized by congenital stationary night blindness and the Mizuo-Nakamura phenomenon which is a unique morphological and functional abnormality of the retina that presents with a typical golden-yellow or silver-gray discoloration of the fundus in the presence of light that disappears after dark-adaptation and appears again after the onset of light. Patients have non progressive night blindness since young childhood with normal day vision, but they often claim improvement of light sensitivities when they remain a long time in a dark environment. Eye fundus shows the Mizuo-Nakamura phenomenon as the only fundus feature. A prolonged dark adaptation of 3 hours or more leads to disappearance of the Mizuo-Nakamura phenomenon fundus changes. No evidence of spicules, macular changes or chorioretinal atrophy is observed. Normal visual acuity, normal caliber of retinal blood vessels and usually normal cone response on electroretinogram (ERG) recording suggest retinal dysfunction rather than degeneration.

Etiology
Oguchi disease is caused by mutations in the SAG gene coding for arrestin located on chromosome 2q37(Oguchi type 1) or by mutations in the GRK1 gene that codes for the rhodopsin kinase located on the chromosome 13q34 (Oguchi type 2). Remarkably, some mutations in the SAG gene are associated with Oguchi disease and retinitis pigmentosa (RP) in the same family. Some mutations in SAG lead to RP.

Diagnostic methods
The diagnosis is clinical and is based on the presence of night blindness and the observation of the Mizuo-Nakamura phenomenon by funduscopy and electroretinography (ERG). The clinical diagnosis is confirmed by genetic testing.

Differential diagnosis
The differential diagnosis includes Stargardt disease, RP in female carriers, juvenile retinoschisis, and progressive cone dystrophy (see these terms). All these conditions may have fundus changes but without the classical Mizuo-Nakamura phenomenon.

Genetic counseling
Oguchi disease is an autosomal recessive condition. Brothers and sisters of an affected case have a 25% risk to be also affected.

Management and treatment
To date, there is not a specific treatment for Oguchi disease.

Prognosis
In Oguchi disease the visual prognosis is good in absence of progression of symptoms. Although Oguchi disease is categorized as a stationary condition it can lead to reduced visual acuity or constricted visual fields, especially in older patients.

Visit the Orphanet disease page for more resources.

Symptoms

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
HPO ID
Percent of people who have these symptoms is not available through HPO
Autosomal recessive inheritance
0000007
Congenital stationary night blindness
Night blindness since birth
0007642
Hemeralopia
Day blindness
0012047

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

In-Depth Information

  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Oguchi disease. Click on the link to view a sample search on this topic.