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PEOPLE SUFFERING FROM gyrate atrophy of the choroid (the thin
coating of the eye) and retina face a progressive loss of vision, with
total blindness usually occurring between the ages of 40 and 60.
The disease is an inborn error of metabolism.
The gene whose mutation causes gyrate atrophy is found on
chromosome 10, and encodes an enzyme called ornithine ketoacid
aminotransferase (OAT). Different inherited mutations in OAT cause
differences in the severity of symptoms of the disease. OAT
converts the amino acid ornithine from the urea cycle ultimately into
glutamate. In gyrate atrophy, where OAT function is affected, there
is an increase in plasma levels of ornithine.
It is already known that reduction of the amino acid arginine in the
diet has a salutary effect on most patients. Current lines of research
into the disease include: (1) investigating how variant mutations of
the alleles (versions of the gene inherited) interact in order to cause
the differing symptoms of the disease and (2) work on mouse
models of the disease is furthering our understanding, which is
hoped will lead to a true cure.