FASPS is the first disorder to link known core clock genes directly with human circadian sleep disorders. As the PER2 mutation is not exclusively responsible for causing FASPS, current research has continued to evaluate cases in order to identify new mutations that contribute to the disorder. Mechanisms (Per2 and CK1)
Two years after reporting the finding of FASPS, Ptáčeks and Fus groups published results of genetic sequencing analysis on a family with FASPS. They genetically mapped the FASPS locus to chromosome 2q where very little human genome sequencing was then available. Thus, they identified and sequenced all the genes in the critical interval. One of these was Period2 (Per2) which is a mammalian gene sufficient for the maintenance of circadian rhythms. Sequencing of the hPer2 gene (h denoting a human strain, as opposed to Drosophila or mouse strains) revealed a serine-to-glycine point mutation in the Casein Kinase I (CK1) binding domain of the hPER2 protein that resulted in hypophosphorylation of hPER2 in vitro. The hypophosphorylation of hPER2 disrupts the transcription-translation (negative) feedback loop (TTFL) required for regulating the stable production of hPER2 protein. In a wildtype individual, Per2 mRNA is transcribed and translated to form a PER2 protein. Large concentrations of PER2 protein inhibits further transcription of Per2 mRNA. CK1 regulates PER2 levels by binding to a CK1 binding site on the protein, allowing for phosphorylation which marks the protein for degradation, reducing protein levels. Once proteins become phosphorylated, PER2 levels decrease again, and Per2 mRNA transcription can resume.
Nikki may refer to:

Arts and entertainment
Fictional characters
Nikki (Barbie), a fashion doll in the Barbie toy line
Nikki (comics), a Marvel Comics character
Nikki and Paulo, from the TV series Lost
Nikki, the mascot of Swapnote
Nikki, the main character from Dork Diaries

Music
Nikki (album), by Nikki Yanofsky, 2010
Nikki, an album by Quruli, 2005
"Nikki" (song), by Forever the Sickest Kids, 2013
"Nikki", a song by Logic from Under Pressure, 2014
"Nikki", an instrumental composition by Burt Bacharach

Other media
Nikki (DC Thomson), a 1980s girls comic
Nikki (TV series), a 2000s American series starring Nikki Cox
Nikki, Wild Dog of the North, a 1961 Walt Disney film

People
Nikki (given name), including a list of people with the name

Singers
Nikki (singer), Japanese-American singer
Nikki (Malaysian singer), Nikki Palikat (born 1985), a finalist in the first season of Malaysian Idol
Nigar Jamal (born 1980) or Nikki, English-Azerbaijani singer

Other uses
Nikki (drug), marketing name of a birth control pill
Nikki, Benin, a city, arrondissement and commune

See also

Nicci (disambiguation)
Nicki (disambiguation)
Nicky (disambiguation)
Nickey (disambiguation)
Nickie (disambiguation)
Nique (disambiguation)
All pages with titles beginning with Nikki
All pages with titles containing Nikki
Nikii Daas
NikkieTutorials
Nikky Finney
Nikky
Niky