the mechanism of lupus is not well understood, it is both the genetic susceptibility and the environment factor whis is responsible for the disease. it ususlly afects females and it is rare in males. genetic testing will give you an idea that he is a susceptible person but development of the disease is not garunteed. well the presence of the gene can be tested, but it is not offered as pre conceptional genetic testing. you have to visit a specality center and get it tested and counceled by the senior doctors