Mapping and identification of autoimmunity genes

Over the past several years, intense effort has been made to map the chromo somal locations of genes involved in the susceptibility to autoimmune disea ses. The first phase of this mapping effort - performed in most cases by us ing microsatellite markers to scan the genome for loci that are linked with disease - has generated first-draft maps for numerous autoimmune diseases in humans, mice and rats, pointing to as many as 20 different loci in some diseases. The second phase is now beginning, with efforts focused on narrow ing the loci sufficiently to allow the positional cloning of disease-associ ated alleles. From these mapping data it is clear that some of these loci o verlap between various autoimmune diseases and preliminary results suggest that indeed there is a sharing of 'autoimmunity genes' between various auto immune diseases.