CRY1 and cyclic hematopoiesis: Four single nucleotide polymorphisms (SNPs) have been chosen for screening in our Swedish CH case-control material due to evidence of association with neurological and psychiatric disorders in previous studies and their potential effect on gene expression and/or function; rs2287161 (downstream of CRY1), rs8192440 (in exon 5 in CRY1 leading to a silent mutation), rs10838524 (in intron 1 in CRY2), and rs1554338 (downstream of CRY2) (16,17,19,21).