advanced sleep phase syndrome

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 night (e.g. midnight, 1:00, etc.).

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 (FASPS)

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.^[1]

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^[2] and mouse^[3] models, which produced short-day mutants and were predicted to produce a phase advance in humans.^[4] 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.^[5]

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.^[6] The evidence for both of these reported causes of FASPS is strengthened by the absence of said mutations in all tested control subjects.^[5][6]

See also

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

References

1. ^ Jones, Christopher R.; Scott S. Campbell, Stephanie E. Zone, et al. (September 1999). "Familial advanced sleep-phase syndrome: A short-period circadian rhythm variant in humans". Nature Medicine 5 (9): 1062-1065. DOI:10.1038/12502. PMID 10470086. Retrieved on 6 May 2007. 
2. ^ Konopka, Ronald J.; Seymour Benzer (September 1971). "Clock mutants of Drosophila melanogaster". Proceedings of the National Academy of Sciences 68 (9): 2112-2116. PMID 5002428. Retrieved on 6 May 2007. 
3. ^ Zehng, Binhai; David W. Larkin, Urs Albrecht, et al. (8 July 1999). "The mPer2 gene encodes a functional component of the mammalian circadian clock". Nature 400 (6740): 169-173. DOI:10.1038/22118. PMID 10408444. Retrieved on 6 May 2007. 
4. ^ Klerman, E. B.; D. J. Dijk, R. E. Kronauer, C. A. Czeisler (January 1996). "Simulations of light effects on the human circadian pacemaker: implications for assessment of intrinsic period". American Journal of Physiology 270 (1): 271-282. PMID 8769811. Retrieved on 6 May 2007. 
5. ^ ^{a b} Toh, Kong L.; Christopher R. Jones, Yan He, et al. (9 February 2001). "An hPer2 phosphorylation site mutation in familial advanced sleep phase syndrome". Science 291 (5506): 1040-1043. DOI:10.1126/science.1057499. PMID 11232563. Retrieved on 6 May 2007. 
6. ^ ^{a b} Xu, Ying; Quasar S. Padiath, Robert E. Shapiro, et al. (31 March 2005). "Functional consequences of a CKIδ mutation causing familial advanced sleep phase syndrome". Nature 434 (7033): 640-644. DOI:10.1038/nature03453. PMID 15800623. Retrieved on 6 May 2007. 

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