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Leber congenital amaurosis 8(LCA8)

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: CRB1-Related Leber Congenital Amaurosis; LCA8
Gene (location): CRB1 (1q31.3)
Monarch Initiative: MONDO:0013453
OMIM®: 613835


Leber congenital amaurosis comprises a group of early-onset childhood retinal dystrophies characterized by vision loss, nystagmus, and severe retinal dysfunction. Patients usually present at birth with profound vision loss and pendular nystagmus. Electroretinogram (ERG) responses are usually nonrecordable. Other clinical findings may include high hypermetropia, photodysphoria, oculodigital sign, keratoconus, cataracts, and a variable appearance to the fundus (summary by Chung and Traboulsi, 2009). For a general description and a discussion of genetic heterogeneity of LCA, see 204000. [from OMIM]

Additional description

From MedlinePlus Genetics
Leber congenital amaurosis, also known as LCA, is an eye disorder that is present from birth (congenital). This condition primarily affects the retina, which is the specialized tissue at the back of the eye that detects light and color. People with this disorder typically have severe visual impairment beginning at birth or shortly afterward. The visual impairment tends to be severe and may worsen over time.

Leber congenital amaurosis is also associated with other vision problems, including an increased sensitivity to light (photophobia), involuntary movements of the eyes (nystagmus), and extreme farsightedness (hyperopia). The pupils, which usually expand and contract in response to the amount of light entering the eye, do not react normally to light. Instead, they expand and contract more slowly than normal, or they may not respond to light at all.

A specific behavior called Franceschetti's oculo-digital sign is characteristic of Leber congenital amaurosis. This sign consists of affected individuals poking, pressing, and rubbing their eyes with a knuckle or finger. Poking their eyes often results in the sensation of flashes of light called phosphenes. Researchers suspect that this behavior may contribute to deep-set eyes in affected children.

In very rare cases, delayed development and intellectual disability have been reported in people with the features of Leber congenital amaurosis. Because of the visual loss, affected children may become isolated. Providing children with opportunities to play, hear, touch, understand and other early educational interventions may prevent developmental delays in children with Leber congenital amaurosis.

At least 20 genetic types of Leber congenital amaurosis have been described. The types are distinguished by their genetic cause, patterns of vision loss, and related eye abnormalities.  https://medlineplus.gov/genetics/condition/leber-congenital-amaurosis

Clinical features

From HPO
Eye poking
MedGen UID:
Concept ID:
Mental or Behavioral Dysfunction
Repetitive pressing, poking, and/or rubbing in the eyes.
MedGen UID:
Concept ID:
Disease or Syndrome
A cone-shaped deformity of the cornea characterized by the presence of corneal distortion secondary to thinning of the apex.
MedGen UID:
Concept ID:
Disease or Syndrome
Rhythmic, involuntary oscillations of one or both eyes related to abnormality in fixation, conjugate gaze, or vestibular mechanisms.
MedGen UID:
Concept ID:
Disease or Syndrome
A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.
Reduced visual acuity
MedGen UID:
Concept ID:
Diminished clarity of vision.
Deeply set eye
MedGen UID:
Concept ID:
An eye that is more deeply recessed into the plane of the face than is typical.
Coloboma of macula
MedGen UID:
Concept ID:
Congenital Abnormality
A congenital defect of the macula distinct from coloboma associated with optic fissure closure defects. Macular coloboma is characterized by a sharply defined, rather large defect in the central area of the fundus that is oval or round, and coarsely pigmented.
Undetectable electroretinogram
MedGen UID:
Concept ID:
Lack of any response to stimulation upon electroretinography.
Hyperopia, high
MedGen UID:
Concept ID:
A severe form of hypermetropia with over +5.00 diopters.
Choriocapillaris atrophy
MedGen UID:
Concept ID:
Atrophy of the capillary lamina of choroid.
Chorioretinal atrophy
MedGen UID:
Concept ID:
Disease or Syndrome
Atrophy of the choroid and retinal layers of the fundus.
Nummular pigmentation of the fundus
MedGen UID:
Concept ID:
Clumped pigmentary changes of nummular appearance (i.e., thought to resemble the shape of a coin or multiple coins stuck together) at the level of the retinal pigment epithelium.
Pigmentary retinopathy
MedGen UID:
Concept ID:
Disease or Syndrome
An abnormality of the retina characterized by pigment deposition. It is typically associated with migration and proliferation of macrophages or retinal pigment epithelial cells into the retina; melanin from these cells causes the pigmentary changes. Pigmentary retinopathy is a common final pathway of many retinal conditions and is often associated with visual loss.

Professional guidelines


Huang CH, Yang CM, Yang CH, Hou YC, Chen TC
Genes (Basel) 2021 Aug 19;12(8) doi: 10.3390/genes12081261. PMID: 34440435Free PMC Article
Yi Z, Sun W, Xiao X, Li S, Jia X, Li X, Yu B, Wang P, Zhang Q
Exp Eye Res 2021 Jul;208:108637. Epub 2021 May 26 doi: 10.1016/j.exer.2021.108637. PMID: 34048777
Galvin JA, Fishman GA, Stone EM, Koenekoop RK
Retina 2005 Oct-Nov;25(7):919-29. doi: 10.1097/00006982-200510000-00016. PMID: 16205573

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