Two of the most common diseases affecting the stroma are "granular" and "lattice" corneal dystrophies. Since their recognition in the last century, it has been assumed that these conditions were biochemically and genetically distinct. In 1985, Dr. Folberg (now at the University of Iowa) identified a new disease in which features of granular and lattice corneal dystrophies were present in the same patients suggesting that these diseases could be closely related biochemically. Since the ancestors of the first several families found with this condition could all be traced to a small province of Italy known as Avellino, this combination dystrophy has become known as Avellino corneal dystrophy.
Granular corneal dystrophy.
In collaboration with investigators at the University of Minnesota and University of Pennsylvania, we were able to study four large families with Avellino dystrophy as well as two families each with pure granular and pure lattice dystrophies. In early 1994, we mapped the gene for Avellino dystrophy to the long arm of chromosome 5. Interestingly, the genes for both of the "pure" dystrophies mapped to the identical location, strongly suggesting that all three diseases are caused by mutations in the same gene.
Avellino is a small town in central Italy east of Naples (marked with yellow dot). All of the first group of patients with combined lattice and granular corneal dystrophy traced their ancestry to this small town.
The material deposited in the corneas of patients affected with these dystrophies is a substance known as amyloid and is related to the substance that accumulates in the brains of some patients with Alzheimer's disease. We are hopeful that the identification of the molecular cause of these corneal dystrophies will allow an effective treatment to be developed. Since the corneal deposits can be directly visualized in living patients, potential treatments for this disorder will be much easier to evaluate than similar treatments designed to lessen the hidden brain deposits of Alzheimer's patients. We believe that when a successful treatment can be developed for the corneal amyloidoses, it will be a major step toward successfully treating Alzheimer's disease as well.
