HLA-DR restriction-fragment-length polymorphisms in narcolepsy.

Seventeen white patients from the Stanford Sleep Disorders Clinic complaining of excessive daytime somnolence (EDS) were selected for restriction-fragment-length polymorphism (RFLP) studies. Fourteen of the patients with clinically diagnosed narcolepsy were seropositive for DR2. RFLP analysis of these patients compared with a homozygous DR2-Dw2 cell line failed to reveal any polymorphism when digested with six restriction endonucleases and hybridized with three different cDNA probes. None of the three patients with central nervous system hypersomnia, a syndrome similar to narcolepsy, were DR2-positive. We conclude that any polymorphism of the DR beta, DQ alpha, or DQ beta genes of DR2 narcoleptics that might distinguish them from DR2 normals cannot be resolved through RFLP analysis.