Rs121912617

rs121912617, also known as Pro384Arg or P384R, is a SNP in the basic helix-loop-helix family, member e41 BHLHE41 gene. Note that some publications and OMIM refer to this as Pro385 (rather than 384).

replicated

Individuals heterozygous for rs121912617 are known as Familial Natural Short Sleepers (FNSS), and they sleep 6–6.5 hours per night (∼2 hours less than controls) on average, without reporting any sense of sleep deprivation. This is classified as a sleep disorder, although it does not appear to have any known negative medical consequence.