Choroideremia is a rare retinal condition which is transmitted from female carriers to their sons, with a 50% chance on each pregnancy of passing the x gene with the mistake onto the child. The symptoms are similar to RP but the progressive loss of vision is caused by degeneration of both the choroid, the network of blood vessels between the retina and the sclera - the white of the eye, and the retinal cells. The gene has been isolated and the gene product - Rab escort Protein-1, identified. Dr lan McDonald of the University of Alberta, Canada, has developed a test to see if the protein is present or absent in possibly affected males. In male patients with Choroideremia, the protein is missing. Dr Jacquie Greenberg, one of our researchers at UCT, arranged for our families to be tested and blood samples from South Africa were shipped to Canada in August. This type of international collaboration is typical of our excellent researchers.