rs1801260, a SNP in the CLOCK gene known as 3111 T/C, has been reported to influence sleep and activity patterns in patients affected by bipolar depression. [PMID 17221848]
From this article's abstract:
"Compared to T/T homozygotes, carriers of the C allele had a similar degree of severity of depression, but showed higher activity levels in the evening, a delayed sleep onset (mean 79 min later), and a reduced amount of sleep during the night (mean 75 min less)."
[PMID 20364331] Allele frequencies of T3111C SNP of hClock were significantly different between schizophrenics and controls (chi(2) = 19.738, P < 0.05). Schizophrenics had a significantly higher frequency of the C allele compared with controls (OR = 2.613, 95% CI = 1.693-4.034). (Han Chinese population.)
[PMID 17948273] There was a strong, significant association (P < 0.001) between both self-rating and interview-based adult ADHD assessments and the rs1801260 polymorphism with at least one T-mutation being the risk allele.
[PMID 20065968] rs1801260 variations associated with weight loss while on Mediterranian diet. Carriers of the G allele displayed greater difficulty in losing weight than non-carriers.
[PMID 17428266] CLOCK 3111 T/C SNP was associated with activity levels in the second part of the day, neuropsychological performance and BOLD fMRI correlates (interaction of genotype and moral valence of the stimuli).
[PMID 20704703] Association study between a polymorphism at the 3'-untranslated region of CLOCK gene and attention deficit hyperactivity disorder
[PMID 21773969] Functional polymorphisms of circadian positive feedback regulation genes and clinical outcome of Chinese patients with resected colorectal cancer
[PMID 22517501] Rotating night shift work and polymorphism of genes important for the regulation of circadian rhythm
[PMID 18071340] Association between polymorphisms in the Clock gene, obesity and the metabolic syndrome in man.
[PMID 18228528] Clock genes may influence bipolar disorder susceptibility and dysfunctional circadian rhythm.
[PMID 18663240] Genetic differences in human circadian clock genes among worldwide populations.
[PMID 18957941] Genome-wide association scan for five major dimensions of personality.
[PMID 19166596] Circadian polymorphisms associated with affective disorders.
[PMID 20180986] CLOCK is suggested to associate with comorbid alcohol use and depressive disorders.
[PMID 20368993] ARNTL (BMAL1) and NPAS2 gene variants contribute to fertility and seasonality.
[PMID 20396431] Genotyping sleep disorders patients.
[PMID 20600471] Association between CLOCK 3111T/C and preferred circadian phase in Korean patients with bipolar disorder.
[PMID 22310473] SIRT1 and CLOCK 3111T>C combined genotype is associated with evening preference and weight loss resistance in a behavioral therapy treatment for obesity.
[PMID 23131019] Physical Activity and Sex Modulate Obesity Risk Linked to 3111T/C Gene Variant of the CLOCK Gene in an Elderly Population: The SUN Project
[PMID 22709985] "Circadian locomotor output cycles kaput (CLOCK) molecule plays major roles in circadian rhythmicity and regulates daily physiological processes including digestive activity. Therefore, we hypothesized that the CLOCK 3111T/C single nucleotide polymorphism (SNP) might have adverse effects on the regulation of gastric motility."
[PMID 20961464] "The clock molecule plays major roles in circadian rhythmicity and regulating lipid and glucose metabolism in peripheral organs. Disruption of the circadian rhythm can lead to cardiometabolic disorders."
[PMID 23399917] "Here, we find that cholecystokinin (Cck) is a direct transcriptional target of CLOCK and levels of Cck are reduced in the ventral tegmental area (VTA) of ClockΔ19 mice. Selective knockdown of Cck expression via RNA interference in the VTA of wild-type mice produces a manic-like phenotype"
[PMID 24467926] " C genetic variants in CLOCK 3111 T/C are more obese and lose less weight in a dietary and behavioral treatment for obesity than TT carriers and they are also more evening-type subjects "