PTPA and hypersomnia: A comparative study of Caucasian patients with HLA-DQB1*06:02 negative hypersomnia revealed that rs10988217, the SNP in the PPP2R4-CRAT region, was significantly associated with HLA-DQB1*06:02 negative hypersomnia in this population (P-value of 2.51E-02, per-allele OR of 1.25 with 95% CI of 1.03–1.52) (Table 2); these finds were similar to those from the GWAS of Japanese patients with HLA-DQB1*06:02 negative EHS (P-value of 3.43E-06, per-allele OR of 1.52 with 95% CI of 1.13–2.04) (Table 1).