extremely likely lupus genes exist) are currently being explored, some of the genes have clearly been identified (e.g. FcyRIIA; FcyRIIIA; complement components C2, C4 and Clq; PDCD-2; and HLA - DR).

This information indicates, first, that people who have lupus genes have a genetic predisposition to the disease, or a higher likelihood of developing it, than the general population. Merely having lupuslinked genes is not enough to cause a person to develop lupus. This in turn indicates that an external or environmental trigger is also involved in lupus disease onset in people with genetic predisposition.

(Known triggers include stress, hormonal changes, illness, certain viruses including Epstein-Barr virus and chemical exposure.)

Lupus geneticists have been conducting familial studies of lupus for a decade. They study families that are both multiplex (families with 2 or more patients) and simplex (families with one patient) for lups. These two kinds of families are useful in different ways for finding the lupus genes. Multiplex family research allows for the study of inheritable lupus, or lupus that is passed on genetically. These studies use DNA samples (usually blood) from the lupus patients and other unaffected family members whose relationships may prove useful for genetic linkage, usually parents, siblings, grandparents, etc. Simplex family research allows for the study of randomly - occurring lupus, or cases in which the lupus - associated genes come together arbitrarily to create a predisposition to disease. These studies use DNA samples (usually blood) from nuclear families, typically a lupus patient, 1 - 2 siblings and their parents.

By examining the genes of multiplex lupus families (comparing the genes of those affected by lupus and the genes of their unaffected family members ) scientists are locating “hot spots” within the human genome worthy of more specific study. Multiplex lupus studies have also