The sleep-wake cycle is primarily controlled by the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN is dubbed as the master clock of the body, regulating the times at which we fall asleep, wake up, feel hunger, and experience changes in body temperature. The function of the circadian clock is aligned with nature’s 24-hour day-night cycle. However, the circadian clock and the day-night cycle can become unsynchronized with each other due to internal disorders or external changes. The external changes may be associated with travelling to different time zones or changes in work schedule.
On the other hand, the internal disorders that affect the timing of the circadian clock may be due to improper hormonal secretion or genetic problems. One of the recent discoveries regarding the function of the circadian clock is that a sleep phase irregularity called the advanced sleep phase syndrome (ASPS) can be genetic in nature. Accordingly, this is the first hereditary sleep disorder found in humans.
Advanced Sleep Phase Syndrome and Genetic Mutations
Familial advanced sleep phase syndrome (FASPS) is the term used by researchers to label ASPS that is caused by changes in the genetic makeup. Studies show that there is no single gene that is solely responsible for FASPS. Research is ongoing to track down all these genes but as of the moment, only two genes, the hPer2 gene and the casein kinase I delta protein have been determined. Mutation in the hPer2 gene is caused by a change from the amino acid serine to glycine while in the case of casein kinase I delta protein, the amino acid threonine was substituted by alanine at position 44. These mutations caused the shortening of circadian period and hence, ASPS.
The Implications of Advanced Sleep Phase Syndrome on Affected Individuals
Years ago, ASPS was thought to be a rare condition but this is due to the fact that most people who were suffering from this circadian rhythm disorder found nothing very disturbing about their condition and thus rejected the idea of seeking medical help. They did not experience sleep deprivation unlike those with delayed sleep phase and the quality of their sleep was perfectly normal. The only problem they had was that they fell asleep earlier and woke up earlier than the conventional schedule. However, since it is still not the normal time for sleeping and waking up, ASPS patients may experience a decrease in energy and alertness during the afternoon which could affect their work and family life.
Conclusion on the Discovery of the Familial Advanced Sleep Phase Syndrome Gene
The discovery is very beneficial for the treatment of ASPS since many treatments are aiming only for the superficial symptoms of the condition. By targeting the genetic factors of the sleep phase irregularity, treatments can be more successful and this will give ASPS patients a chance to adjust their sleeping schedule to be more in sync with their work and family life.
