Familial advanced sleep phase syndrome (FASPS)

Hereditary sleep disturbance characterized by drowsiness in the early afternoon, when other people are active, and earlier than usual awakenings.

Familial advanced sleep phase syndrome (FASPS) is a very rare circadian sleep rhythm disorder characterised by the presence of a recurrent pattern of early nighttime sleepiness and early awakening that can lead to emotional and physical disturbances.

Sleep phase advancement can occur for various reasons and can be sporadic, however, there is a familial form that follows an autosomal dominant inheritance pattern caused by mutations in the PER2 and CSNK1D genes, both of which are involved in the regulation of the circadian rhythm.

Although sleep-wake cycle disturbances in adults are relatively common, FASPS is a rare disorder affecting 1% of middle-aged adults.


FASPS results in an earlier sleep phase by 4 to 6 hours compared to the average. This results, in many cases, in a sleep deficit leading to excessive daytime sleepiness. Patients with FASPS experience normal quality and quantity of sleep, however, sleep deprivation may be imposed by social norms that cause individuals to delay bedtime. Therefore, this can interfere significantly in the social and work life of the affected person, causing emotional and physical disorders.

Disease management

Due to the physiological alterations in the regulation of the circadian rhythm in affected individuals, there are no effective preventive measures. However, once diagnosed, there are therapeutic actions to try to control it. Currently, treatment with bright light at night is available in order to delay the onset of sleep and promote its compensation, as well as the administration of melatonin prescribed by a specialist.

Genes analyzed



Bchetnia M, Tardif J, Morin C, et al.Expression signature of the Leigh syndrome French-Canadian type. Mol Genet Metab Rep. 2022 Feb 5;30:100847.

Mol Genet Metab Rep. 2022 Feb 5;30:100847.

Mootha VK, Lepage P, Miller K, et al.Identification of a gene causing human cytochrome c oxidase deficiency by integrative genomics. Proc Natl Acad Sci U S A. 2003 Jan 21;100(2):605-10. doi: 10.1073/pnas.242716699.

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