HLA typing does not predict REM sleep behaviour disorder and hallucinations in Parkinson's disease.

HLA-DR2 haplotype and DQ1 DNA alleles, characterizing 90 to 100% of all narcoleptic patients, were found to be equally distributed in 20 Parkinson's disease (PD) patients with early hallucinations, rapid eye movement (REM) sleep-related behaviour disturbances (RBD), and sleep onset in REM (SOREM), and in 20 PD patients without hallucinations, despite 10 to 15 years of treatment, and no RBD or SOREM.