DEC2 or BHLHE41

"Basic helix-loop-helix family, member e41", or BHLHE41, is a gene that encodes, as the name implies, a basic helix-loop-helix protein in various tissues of both humans and mice. It also known as DEC2, hDEC2, and SHARP1, and was previously known as "basic helix-loop-helix domain containing, class B, 3", or BHLHB3. Defects in this gene are associated with the short sleep phenotype. A particular genetic variation in the gene affects sleep duration in humans, and introduction of the human gene into mice also reduces their sleep requirements. This genetic variation was discovered by Ying-Hui Fu's lab.