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Leber's Congenital Amaurosis
What is Leber's
congenital amaurosis?
What treatment is
available?
LCA is an inherited retinal
degenerative disease characterized by
severe loss of vision at birth. A variety
of other eye-related abnormalities
including roving eye movements, deepset eyes, and sensitivity to bright light
also occur with this disease. LCA is an
inherited disorder. It follows the
autosomal recessive pattern of
inheritance, which means that both
parents must have a gene in order for
their child to have the disorder. Some
LCA types are progressive in that they
become more severe with age and some
are stationary in that there is little
change noted with time.
There is no cure for LCA. However,
scientists have identified 14 genes with
mutations that can each cause LCA.
These genes account for approximately
75 percent of all cases of LCA.
Researchers at Children's Hospital of
Philadelphia and the University of
Pennsylvania have treated six young
people via gene therapy. Clinical trials
of gene replacement therapy for LCA
caused by mutations in the RPE65 are
now beginning. It is the same therapy
that gave vision to 50 dogs, including
the world-famous Lancelot, born blind
from LCA.
Signs and symptoms
Individuals with LCA have very
reduced vision at birth. Within an
infant’s first few months of life, parents
usually notice a lack of visual
responsiveness and unusual roving eye
movements, known as nystagmus
(roving eye). By early adolescence,
various changes in the retinas of
patients with LCA become readily
apparent. Symptoms may include lens
opacity (cataract), aversion to light
(photophobia), hearing impairment and
possibly developmental delays,
keratoconus (cone shape to the front of
the eye) and the oculo-digital reflex
(repeated pressing of the eyes with the
hands or fists)
Diagnosis
A key feature of LCA is an abnormally
low electrical response of the retina.
Retinal blood vessels can become thin
and narrow and there can be
pigmentary changes that an
Ophthalmologist can see within the
eye. This can be measured by using a
method called Electroretinography. In
this procedure, the retina is stimulated
by light and the electrical response
pattern is recorded on an
electroretinogram (ERG) and compared
with ERG responses from normal
subjects.
Sources:
1. http://www.tfrr.org/
2. http://www.tsbvi.edu/Outreach/
seehear/spring01/lebers.htm
3. http://en.wikipedia.org/wiki/Leb
er's_congenital_amaurosis
4. http://www.blindness.org/vision
disorders/causes.asp?type=13
5. http://www.healthcentral.com/e
ncyclopedia/408/468.html
Leber's Congenital Amaurosis