Editing Advanced sleep phase disorder (section)

=== FASPS symptoms ===
While advanced sleep and wake times are relatively common, especially among older adults, the extreme phase advance characteristic of familial advanced sleep phase syndrome (also known as familial advanced sleep phase disorder) is rare. Individuals with FASPS fall asleep and wake up 4–6 hours earlier than the average population, generally sleeping from 7:30pm to 4:30am. They also have a free running [[Circadian clock|circadian period]] of 22 hours, which is significantly shorter than the average human period of slightly over 24 hours.<ref>{{Cite journal|last1=Jones|first1=Christopher R.|last2=Huang|first2=Angela L.|last3=Ptáček|first3=Louis J.|last4=Fu|first4=Ying-Hui|date=2013|title=Genetic Basis of Human Circadian Rhythm Disorders|journal=Experimental Neurology|volume=243|pages=28–33|doi=10.1016/j.expneurol.2012.07.012|issn=0014-4886|pmc=3514403|pmid=22849821}}</ref> The shortened period associated with FASPS results in a shortened period of activity, causing earlier sleep onset and offset. This means that individuals with FASPS must delay their sleep onset and offset each day in order to entrain to the 24-hour day. On holidays and weekends, when the average person's sleep phase is delayed relative to their workday sleep phase, individuals with FASPS experience further advance in their sleep phase.<ref name=":0">{{Cite journal|last1=Tafti|first1=Mehdi|last2=Dauvilliers|first2=Yves|last3=Overeem|first3=Sebastiaan|date=2007|title=Narcolepsy and familial advanced sleep-phase syndrome: molecular genetics of sleep disorders|journal=Current Opinion in Genetics & Development|language=en|volume=17|issue=3|pages=222–227|doi=10.1016/j.gde.2007.04.007|pmid=17467264}}</ref>

Aside from the unusual timing of sleep, FASPS patients experience normal quality and quantity of sleep. Like general ASPD, this syndrome does not inherently cause negative impacts, however, [[sleep deprivation]] may be imposed by social norms causing individuals to delay sleep until a more socially acceptable time, causing them to losing sleep due to earlier-than-usual wakeup time.<ref name=":0" />

Another factor that distinguishes FASPS from other advanced sleep phase disorders is its strong familial tendency and life-long expression. Studies of affected lineages have found that approximately 50% of directly related family members experience the symptoms of FASPS, which is an [[Dominance (genetics)|autosomal dominant trait]].<ref>{{Cite journal|last1=Pack|first1=Allan I.|last2=Pien|first2=Grace W.|date=18 February 2011|title=Update on Sleep and Its Disorders|journal=Annual Review of Medicine|language=en|volume=62|issue=1|pages=447–460|doi=10.1146/annurev-med-050409-104056|pmid=21073334|issn=0066-4219}}</ref> Diagnosis of FASPS can be confirmed through genetic sequencing analysis by locating genetic mutations known to cause the disorder. Treatment with sleep and wake scheduling and bright light therapy can be used to try to delay sleep phase to a more conventional time frame, however treatment of FASPS has proven largely unsuccessful.<ref>{{Cite journal|last1=Fu|first1=Y. H.|last2=Ptáček|first2=L. J.|last3=Chong|first3=S. Y.|date=2012|title=Genetic insights on sleep schedules: this time, it's PERsonal.|journal=Trends in Genetics|volume=28|issue=12|pages=598–605|doi=10.1016/j.tig.2012.08.002|issn=0168-9525|pmid=22939700|pmc=3500418}}</ref> Bright light exposure in the evening (between 7:00 and 9:00), during the delay zone as indicated by the [[phase response curve]] to light,<ref name=":33"/> has been shown to delay circadian rhythms, resulting in later sleep onset and offset in patients with FASPS or other advanced sleep phase disorders.<ref name=":25"/>