Lavebratt C, Sjöholm LK, Soronen P, Paunio T, Vawter MP, Bunney WE, Adolfsson R, Forsell Y, Wu JC, Kelsoe JR, Partonen T, Schalling M. PLoS One. 2010 Feb 24;5(2):e9407.
To determine the role of cry2 in bipolar disorder, winter depression and sleep deprivation, the authors performed two separate studies in Swedes and Finns.
First, they subjected patients with bipolar disorder (n=13, diagnosed according to DSM-IV criteria) and (n=8) healthy controls to sleep deprivation, and found that cry2 gene expression was increased only in healthy individuals.
Next, they recruited and genotyped bipolar patients from psyciatric specialists and matched controls from the general population. They found that in both the Finnish (n=1182) and Swedish (n=1129) samples, those with seasonal affective disorder were more likely to have risk alleles for SNPs (rs10838524A-rs10838527G-rs3824872A) in the cry2 gene.
The SNPs in cry2