Leber's congenital amaurosis

Leber's congenital amaurosis

[lā′bərz]

Etymology: Theodor von Leber, German ophthalmologist, 1840-1917; L, congenitus, born with; Gk, amauroein, to darken

a rare kind of blindness or severely impaired vision caused by a defect transmitted as an autosomal-recessive trait and occurring at birth or shortly thereafter. The eyes appear normal externally, but pupillary constriction to light is sluggish or absent, and electroretinographic responses are decreased or absent. Pendular nystagmus, photophobia, cataract, and keratoconus may be present; the ophthalmic disorder may be associated with mental retardation and epilepsy. One type of Leber's amaurosis results in complete blindness. In a second kind the pathology does not progress, and the patient has very mild vision loss.

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Leber's congenital amaurosis

A hereditary, bilateral blindness present at birth or in early childhood. It is caused by mutations in the gene encoding the retinal guanylate cyclase (GUCY2D) on chromosome 17. Initially, the ocular fundus appears normal, although the ERG is markedly reduced. A salt and pepper fundus and optic atrophy appear later. The condition is often accompanied by nystagmus and photophobia.