Advanced sleep phase syndrome

Infobox_Disease
Name = Advanced sleep phase syndrome


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ICD9 = ICD9|327.32
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MeshID = D020178

Advanced sleep phase syndrome (ASPS), also known as the advanced sleep-phase type (ASPT) of circadian rhythm sleep disorder, is a condition in which patients feel very sleepy early in the evening (e.g. 18:00-19:00) and wake up very early in the morning (e.g. 03:00).

ASPS is frequently encountered in the elderly and in post-menopausal women. It can be treated pharmacologically, with evening bright lights, or behaviorally with chronotherapy or free-running sleep.

Familial advanced sleep phase syndrome

In 1999, Louis Ptáček’s research group at the University of California, San Francisco reported findings of a human circadian rhythm disorder showing a familial tendency. The disorder was characterized by a life-long pattern of sleep onset around 7:30pm and offset around 4:30am. Among three lineages, 29 people were identified as affected with this familial advanced sleep-phase syndrome (FASPS), and 46 were considered unaffected. The pedigrees demonstrated FASPS to be a highly penetrant, autosomal dominant trait. [cite journal|last=Jones|first=Christopher R.|coauthors=Scott S. Campbell, Stephanie E. Zone, et al.|title=Familial advanced sleep-phase syndrome: A short-period circadian rhythm variant in humans|journal=Nature Medicine|volume=5|issue=9|pages=1062–1065|date=September 1999|url=http://www.nature.com/nm/journal/v5/n9/abs/nm0999_1062.html|doi=10.1038/12502|pmid=10470086|accessdate=2007-05-06]

Two years after reporting the finding of FASPS, Ptáček’s group published results of genetic sequencing analysis on a family with FASPS. To narrow their search they took a cue from research on Per mutations in Drosophila [cite journal|last=Konopka|first=Ronald J.|coauthors=Seymour Benzer|title=Clock mutants of Drosophila melanogaster|journal=Proceedings of the National Academy of Sciences|volume=68|issue=9|pages=2112–2116|date=September 1971|url=http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=5002428|pmid=5002428 |accessdate=2007-05-06|doi=10.1073/pnas.68.9.2112] and mouse [cite journal|last=Zehng|first=Binhai|coauthors=David W. Larkin, Urs Albrecht, et al.|title=The mPer2 gene encodes a functional component of the mammalian circadian clock|journal=Nature|volume=400|issue=6740|pages=169–173|date=8 July 1999|url=http://www.nature.com/nature/journal/v400/n6740/abs/400169a0.html|doi=10.1038/22118|pmid=10408444|accessdate=2007-05-06] models, which produced short-day mutants and were predicted to produce a phase advance in humans. [cite journal|last=Klerman|first=E. B.|coauthors=D. J. Dijk, R. E. Kronauer, C. A. Czeisler|title=Simulations of light effects on the human circadian pacemaker: implications for assessment of intrinsic period|journal=American Journal of Physiology|volume=270|issue=1|pages=271–282|date=January 1996|url=http://ajpregu.physiology.org/cgi/content/abstract/270/1/R271|pmid=8769811|accessdate=2007-05-06] With this guidance they quickly found what they were looking for. Sequencing of the hPer2 gene revealed a serine-to-glycine point mutation in the CK1ε binding domain of the hPER2 protein.cite journal|last=Toh|first=Kong L.|coauthors=Christopher R. Jones, Yan He, et al.|title=An hPer2 phosphorylation site mutation in familial advanced sleep phase syndrome|journal=Science|volume=291|issue=5506|pages=1040–1043|date=9 February 2001|url=http://www.sciencemag.org/cgi/content/abstract/291/5506/1040|doi=10.1126/science.1057499|pmid=11232563|accessdate=2007-05-06]

In 2005, Ptáček’s lab reported discovery of a different mutation causing FASPS. This time the CK1δ was implicated, demonstrating an A-to-G missense mutation that resulted in a threonine-to-alanine alteration in the protein.cite journal|last=Xu|first=Ying|coauthors=Quasar S. Padiath, Robert E. Shapiro, et al.|title=Functional consequences of a CKIδ mutation causing familial advanced sleep phase syndrome|journal=Nature|volume=434|issue=7033|pages=640–644|date=31 March 2005|url=http://www.nature.com/nature/journal/v434/n7033/abs/nature03453.html|doi=10.1038/nature03453|pmid=15800623|accessdate=2007-05-06] The evidence for both of these reported causes of FASPS is strengthened by the absence of said mutations in all tested control subjects.

ee also

* Circadian rhythm sleep disorder
* Delayed sleep phase syndrome
* Non-24-hour sleep-wake syndrome

References