Electrophysiological and immunogenetic findings in recurrent monosymptomatic-type hypersomnia: a study of two unrelated Italian cases.

MSLT and immunogenetic findings in two unrelated Italian subjects with recurrent monosymptomatic hypersomnia are reported. In both patients MSLT documented a markedly increased daytime sleep propensity during the attacks without augmented REM sleep pressure. Both patients share the same HLA haplotype (HLA-DR1, DQ1) which has been found in Kleine-Levin syndrome. This makes these subtypes of recurrent hypersomnia indistinguishable one from the other, under the immunogenetic profile, but permits differentiation from narcolepsy which is HLA-DR2, DQ1 closely linked.