Odds ratios were used to test for associations of the risk allele for each PER3 SNP (the 4-repeat allele of PER3 VNTR, the G-allele of PER3A, the A-allele of PER3B, and the T-allele of PER3C with anxiety, depression, and ID (Table 2); for associations with sleep disturbances and evening chronotype (Table 3); and for sex-specific associations between sleep or mood disorders and PER3 SNPs (Table 4). The gene discussed is PER3; the disease is Sleep disturbance.