[HLA and narcolepsy].

A very strong association has been shown to exist between HLA-DR2/Dw2 and narcolepsy, both in Caucasoid and Mongoloid people. The gene responsible for susceptibility, HLA or linked with HLA, is probably transmitted as an autosomal dominant trait with incomplete penetrance. The investigation of DR2 is useful for the diagnosis of minor or incomplete forms in narcolepsy and in the detection of exposed subjects in families. This association opens up horizons concerning the mechanism of narcolepsy. Several hypotheses are discussed, in particular that of a multifactorial disease, in which an environmental agent and DR2 antigen, functioning as the product of an Ir gene, would play a role.