 DR2 (15 or 16) -DQ6.2 has been found to associate with (idiopathic) narcolepsy-cataplexy  Hypocretin ligand deficiency in the brain and cerebrospinal fluid is also link to narcolepsy-cataplexy.DR15-DQ6 also shows an association with factors (including a genetic factor on chromosome 12p12) involved in familial multiple sclerosis DR15-DQ6 is strongly associated with the development of choroidal neovascular lesions in presumed ocular histoplasmosis syndrome.The DR15-DQ6 haplotype may afford some greater protection against the progression of HIV.