Molecular genetics of cutaneous lupus erythematosus.

The cutaneous forms of lupus erythematosus (LE) are true complex traits, susceptibility to which is determined by multiple factors. Good evidence exists for both genetic and environmental components to this complexity. Several different experimental techniques have found the strongest genetic associations with cutaneous LE to include sequence polymorphisms of genes encoding HLA, TNF-alpha and complement molecules, particularly in anti-Ro-positive patients. Abnormal expression of multiple other cytokines, adhesion molecules and cellular proteins (such as Ro and La) points towards a range of candidate genes that are currently being examined in cutaneous LE. Combinations of specific polymorphisms of genes encoding these immunoregulatory molecules may determine individual susceptibility to LE.