Melatonin profiles and sleep characteristics in boys with fragile X syndrome: A preliminary study

Sleep patterns and endogenous melatonin profiles in 13 fragile X boys betwe en the age of 4.7 and 11.0 years were compared to those of 8 age-matched, n ormal control boys. Parents recorded sleep patterns on a Sleep Diary Chart for 14 consecutive days. Twelve saliva samples were obtained from 8 fragile X participants and all of the controls over 48 hours for the assessment of salivary melatonin profiles. The results showed greater variability in tot al sleep time and difficulty in sleep maintenance in fragile X boys compare d with the control participants, Nocturnal melatonin production, expressed as both peak level and area under the concentration-time curve between 20:0 0 h and 08:00 h, were found to be significantly larger in fragile X boys th an in controls. Additionally, the mean of the minimum daytime melatonin lev els recorded was significantly higher for the fragile X group. Elevated lev els in some fragile X boys relative to the range seen in controls, occurrin g either during the day or at night, or in both segments of the secretory p rofile for some individuals, may be due in part to overactivity of the symp athetic nervous system. Alternative molecular mechanisms leading to changes in melatonin profiles in fragile X are also discussed, (C) 2000 Wiley-Liss , Inc.