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Congenital stationary night blindness 1B(CSNB1B)

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: Night blindness, congenital stationary (complete), 1B, autosomal recessive; NIGHT BLINDNESS, CONGENITAL STATIONARY, COMPLETE, AUTOSOMAL RECESSIVE
Gene (location): GRM6 (5q35.3)
Monarch Initiative: MONDO:0009758
OMIM®: 257270


Autosomal recessive 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 and distinguishing objects in low light (night blindness). For example, they may not be able to identify road signs at night or see stars in the night sky. They also often have other vision problems, including loss of sharpness (reduced acuity), nearsightedness (myopia), involuntary movements of the eyes (nystagmus), and eyes that do not look in the same direction (strabismus).

The vision problems associated with this condition are congenital, which means they are present from birth. They tend to remain stable (stationary) over time. [from MedlinePlus Genetics]

Clinical features

From HPO
MedGen UID:
Concept ID:
Disease or Syndrome
A visual defect characterized by the inability to see as clearly in bright light as in dim light. The word hemeralopia literally means day blindness.
MedGen UID:
Concept ID:
Disease or Syndrome
Nearsightedness, also known as myopia, is an eye condition that causes blurry distance vision. People who are nearsighted have more trouble seeing things that are far away (such as when driving) than things that are close up (such as when reading or using a computer). If it is not treated with corrective lenses or surgery, nearsightedness can lead to squinting, eyestrain, headaches, and significant visual impairment.\n\nNearsightedness usually begins in childhood or adolescence. It tends to worsen with age until adulthood, when it may stop getting worse (stabilize). In some people, nearsightedness improves in later adulthood.\n\nFor normal vision, light passes through the clear cornea at the front of the eye and is focused by the lens onto the surface of the retina, which is the lining of the back of the eye that contains light-sensing cells. People who are nearsighted typically have eyeballs that are too long from front to back. As a result, light entering the eye is focused too far forward, in front of the retina instead of on its surface. It is this change that causes distant objects to appear blurry. The longer the eyeball is, the farther forward light rays will be focused and the more severely nearsighted a person will be.\n\nNearsightedness is measured by how powerful a lens must be to correct it. The standard unit of lens power is called a diopter. Negative (minus) powered lenses are used to correct nearsightedness. The more severe a person's nearsightedness, the larger the number of diopters required for correction. In an individual with nearsightedness, one eye may be more nearsighted than the other.\n\nEye doctors often refer to nearsightedness less than -5 or -6 diopters as "common myopia." Nearsightedness of -6 diopters or more is commonly called "high myopia." This distinction is important because high myopia increases a person's risk of developing other eye problems that can lead to permanent vision loss or blindness. These problems include tearing and detachment of the retina, clouding of the lens (cataract), and an eye disease called glaucoma that is usually related to increased pressure within the eye. The risk of these other eye problems increases with the severity of the nearsightedness. The term "pathological myopia" is used to describe cases in which high myopia leads to tissue damage within the eye.
Night blindness
MedGen UID:
Concept ID:
Disease or Syndrome
Inability to see well at night or in poor light.
Horizontal nystagmus
MedGen UID:
Concept ID:
Disease or Syndrome
Nystagmus consisting of horizontal to-and-fro eye movements.
Congenital stationary night blindness
MedGen UID:
Concept ID:
Congenital Abnormality
A nonprogressive (i.e., stationary) form of difficulties with night blindness with congenital onset.
Bone spicule pigmentation of the retina
MedGen UID:
Concept ID:
Pigment migration into the retina in a bone-spicule configuration (resembling the nucleated cells within the lacuna of bone).

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