Concerning these disorders, CLOCK gene variants have been linked to diurnal preference [9], [10], delayed sleep phase syndrome [11], metabolic syndrome and obesity [12], ARNTL gene variants to bipolar disorder [13], type 2 diabetes and hypertension [14], and NPAS2 gene variants to diurnal preference and seasonal affective disorder [15], [16]. The gene discussed is NPAS2; the disease is hypertensive disorder.