Research Targets (1)

Genetic determinants of myopia:
If both parents are myopic, the probability in children of becoming myopic is at least three times as high as when none of the parents is myopic. There is also a high correlation of refractive errors in twins. Although there is always the confounding factor of "shared" or "inherited" (visual) environments, there is also no doubt that the risk of becoming myopic is genetically determined; some people never become myopic, despite heavy loads of near work. Only recently, the molecular tools became available to screen the genome for loci that correlate with myopia. These tools include the knowledge of closely spaced microsatellite markers with known positions in the genome that permit linkage analyses with refractive errors, PCR, fast computers and powerful statistical packages. Using such techniques, at least 6 autosomal dominant loci for high myopia have been found to date, and 2 X-linked recessive loci. It is clear that additional loci remain to be identified. The goal of these studies is to screen for candidate genes in the respective chromosomal regions. Candidate genes provide new information on possible targets for pharmacological intervention of myopia. There are at least two options how these genes may affect refractive development:

1. They could disrupt the normal organization of the scleral network of collagen fibers, embedded in the proteoglycan-rich extracellular matrix secreted by the scleral fibroblasts.
2. They could determine the "gain" by which visual experience is translated into scleral growth rates ("susceptibility genes"). With high gain, the signals arriving from the retina may make near work too effective in driving axial eye growth.

Therefore, it is important to screen for quantitative trait loci (QTLs) that correlate with (high) myopia in humans and animal models:
Project 2/1 Guggenheim - quantitative genetic analyses of myopia in model organisms, UK
Project 2/2 Malecaze & Calvas - genetics of high myopia (HM) genome screening in humans, France
Project 2/3 Hammond - QTL mapping in twins, UK.

About the signalling cascade and pharmacological intervention of myopia. [>>]