Background: Autism spectrum disorder (ASD) is a neurodevelopmental condition associated with sleep disturbances that may result from abnormalities in melatonin production. The correlations of melatonin levels with the severity of sleep disorder and/or severity of ASD were reported.
Objectives: To evaluate urinary levels of the melatonin metabolite, 6-sulphatoxymelatonin (aMT6s), in children with ASD, and their associations with sleep abnormalities and behavioural impairments.
Methods: Study involved 77 children with ASD and 84 controls aged 2.5‒15.5 years. Sleep disorders were assessed by Children's Sleep Habits Questionnaire. Morning and afternoon levels of aMT6s were determined by radioimmunoassay method. Urinary creatinine levels were assessed by an enzymatic method.
Results: The urinary aMT6s/creatinine values indicate that the night-time melatonin levels are significantly lower in ASD than in controls, but there are no significant differences in the daytime levels. In the ASD group, on average, a 6.8-fold difference between night-time and daytime values of urinary aMT6s/creatinine was found, whereas for the controls a 12.5-fold difference was observed, indicating a lower night-time increase in melatonin levels. In ASD group, the difference in night-time-daytime aMT6s/creatinine value correlated with some types of sleep problems, but not with the severity of ASD.
Conclusion: The results indicate that in ASD there are differences in the patterns of melatonin secretion that may be associated with sleep impairment (Tab. 4, Fig. 2, Ref. 28).
Keywords: autism spectrum disorder; sleep disturbances 6-sulphatoxymelatonin..