Leber's Congenital Amaurosis

Definition

This is 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.

This also is called amaurosis congenital of Leber's, congenital retinal blindness, hereditary epithelial aplasia, and retinal aplasia.

Description

One kind of Leber's amaurosis results in complete blindness, but with a second kind the pathology does not progress and the patient has slight vision.

The eyes appear normal externally, but pupillary constriction to light is sluggish or absent and retinal pigment is degenerated.

In Leber's congenital amaurosis, children are born apparently with an absence of light-gathering cells (rods and cones) of the retina. A lack of visual attentiveness at and shortly after birth is the first sign of the disease.

Often the eyes are deeply set in childhood, and the child will rub the eyes allegedly to stimulate the retina to produce light (oculodigital stimulation). Absence or reduction of the electrical activity of the retina is always observed and is necessary for diagnosis.

Some families will have one or more additional features: cataracts evolving in the first two decades of life, keratoconus, neurosensory hearing impairment, mental retardation, underdevelopment of the balance centers (cerebellum), and some distinctive behavioral mannerisms or stereotypes.

Anomalies of brain stem may be associated with Joubert syndrome.

Causes and Risk Factors

Leber's congenital amaurosis is a group of disorders nearly always inherited as recessive traits. Rarely families with dominant transmission have been reported.

It can also be seen as part of a system of disorders (e.g. neurologic dysfunction, kidney disease, and, rarely, chromosomal imbalance).

It is estimated that ten or more different genes may be responsible for the same disease appearance.

Treatment

Treatment of Leber's congenital amaurosis is symptomatic and supportive. Standard procedures such as genetic counseling and services that benefit the sight-impaired can be helpful.

Questions to Ask Your Doctor

What is causing the impaired vision?

Is this hereditary?

What can be expected; what is the typical progress of the disease?

What treatment do you recommend?

Should genetic counseling be considered?

Are there any clinical trials being done on this condition?