Leber Congenital Amaurosis

Background and History: 

This title actually refers to a group of conditions with a common disease profile.  It is derived from a description of some patients by Theodur Karl Gustav von Leber, the German ophthalmologist who wrote about it in 1869 and pointed out its familial occurrence.  It is today recognized as the most common cause of blindness in infants and young children and accounts for up to 18% of students enrolled in schools for the blind.

Clinical Correlations: 

It is characteristic for children with Leber amaurosis to rub or poke their eyes repeatedly.  This may contribute to a condition known as keratoconus in which the cornea (windshield of the eye) becomes cone-shaped.  The same process likely is responsible for giving the eyes a deep-set appearance known as enophthalmos.

Genetics: 

At least 14 mutant genes have been associated with this condition.  In every case, the pattern of inheritance is autosomal recessive since two gene mutations are necessary for the disease to be expressed.  The parents, who each carry a single mutation, are clinically normal.  However, their children each have a 25% chance of receiving both mutations and being affected.

Diagnosis and Prognosis: 

The diagnosis requires an eye examination by an ophthalmologist.  There are no specific diagnostic signs but usually the combination of severe vision loss combined with non-specific changes in the retina (the light sensing tissue in the back of the eye), and the lack of signs characteristic of other disorders are sufficient to make the diagnosis. 

Such young children should also be evaluated by pediatricians and neurologists to look for other physical abnormalities.  Hearing tests are mandatory.  It is important that children are enrolled in sensory stimulation programs early in order to maximize brain development.  Low vision aids can be helpful for individuals with residual vision.  Older patients may benefit from occupational and vocational therapy.

There is no treatment specifically for most patients with Leber congenital amaurosis.  However, recent studies on one type, LCA2, using gene therapy to replace the defective gene have shown promise.  More than 230 patients have so far been treated and more advanced studies are planned.  So far, these have only been done for one mutant gene and it will be some years until this approach will be clinically available.

Additional Information