girls with Rett syndrome happened because MECP2 A study showed that genetic mutations led to increased deep sleep and decreased rapid eye movement (REM) sleep.
Sleep patterns are generally similar across genetic and clinical characteristics of the patient or the severity of the disease. However, increased hand retardation was associated with a longer duration of a particular sleep phase.
This study is the first of its kind on a phenotype [characterize] Sleep in a large sample of RTT [Rett] girls with MECP2 Mutations,” the researchers wrote. “Impaired sleep on/off switching in RTT since embryonic development [embryo development] It is likely to be associated with (psychological) motor impairment in affected cases MECP2 mutations. “
Mainly ryt due to mutations In the MECP2 The gene affects females almost exclusively. The genetic code for a protein of the same name, which regulates how genes essential to brain development and function are read.
symptoms Rhett They include loss of hand function and speech skills, as well as walking disabilities. Intermittent sleep is included in the RET Diagnostic criteria It is an important consequence of changing brain functions.
Sleep patterns in Rett syndrome
Sleep includes different stages – REM and non-REM. In REM, the stage of sleep where most dreams occur, brain activity and blood pressure increase. This stage is closely related to early brain development. Conversely, non-REM sleep is divided into three stages: stage 1, when eye movement and muscle activity slow down; stage 2, characterized by light sleep and hypothermia; The third stage is characterized by deep sleep.
Previous research has indicated that there are sleep problems in Most cases of RET with MECP2 mutationsincluding nocturnal walking, nocturnal restlessness, and excessive daytime sleepiness.
“Results regarding sleep architecture abnormalities in modality therapy settings remain scarce and inconsistent,” write researchers from France and the Netherlands who investigated a possible association between different sleep traits and clinical and genetic characteristics among patients.
Sleep studies were conducted between 2013 and 2016. The sleep-related parameters of 21 girls were recorded MECP2 gene mutations (from 2 to 20). An average of 1,019 minutes of sleep was recorded.
Rett patients had about two to three times longer (mean value, 82.8 minutes) waking time after sleep initiation than their habit-developing peers. Total sleep time, or the time from start to finish falling asleep minus the time to wake up after sleep initiation, was significantly longer at 515.3 minutes. However, the time to sleep onset was significantly shorter (17.4 minutes).
Compared with the control group, the girls had an increase in non-REM stage 3 sleep (44.2% of total sleep time) in contrast to a lower stage 2 period (31.5%), and also a significantly shorter period of non-REM sleep (15.9%).
They generally did not show significant differences in sleep patterns when comparing mutation types and clinical characteristics. However, stage 1 sleep increased significantly with the severity of the hand disability.
Neither REM sleep nor non-REM sleep stages were associated with the patients’ age during the polysomnography, nor with their age at disease onset.
The results showed an impairment in the ability to maintain sleep with “the most severe clinical cases.” [having] The researchers wrote, noting that RET’s poor sleep continuity may be attributed to underlying genetic mutations and apnea (breathing repeatedly stopping and starting during sleep). Apnea is common in Rett patients. Girls with RET usually have intractable epilepsy, which may cause sleep disturbances.
Limitations of the study, the researchers said, include that there were no patients with mutations other than MECP2. Sleep apnea parameters and medical treatments, which may influence sleep patterns, were also not analyzed.
“Investigating the development of both RTT sleep apnea and (manual) locomotor development in animal models of RTT may be a promising research topic that improves our understanding of RTT sleep problems as reported by their caregivers,” they said.