Abstract
BACKGROUND: Circadian rhythm disturbance has been implicated in depression, and polymorphisms of circadian genes Cry1, Cry2, and Tef are associated with depression. However, the relationship between these genes and depression symptoms in Parkinson's disease (PD) has not been established. METHODS: Four hundred eight subjects with PD participated in this study. Demographics, UPDRS, Mini-Mental Status Examination (MMSE), and Hamilton Rating Scale for Depression (HAMD) were obtained in all subjects. Frequency of polymorphisms of Cry1 rs2287161, Cry2 rs10838524, and Tef rs738499 was determined, and the association between genetic polymorphisms of circadian genes and HAMD scores in patients with PD was examined. RESULTS: Tef, but not Cry1 or Cry2, is associated with HAMD scores in patients with PD in a linear regression model after adjusting for clinical variables (P = 0.004). CONCLUSIONS: The polymorphism of Tef rs738499 is associated with depression symptoms in PD.