Correlations between behavior, memory, sleep-wake and melatonin in Williams-Beuren syndrome.

Williams-Beuren syndrome (WBS), a neurodevelopmental disorder caused by a microdeletion on chromosomic region 7q11.23, presents with peculiar behavioral and neurocognitive phenotypes that are marked by apparently preserved social and communicative abilities, which contrasts with low overall cognitive and particularly visuospatial performance. In addition, parents often report complaints of sleep disorders and behavioral problems of unknown cause. Sleep is a biological phenomenon that is modulated by the plasma concentration of melatonin and with influence on behavioral aspects and memory. Thus, this study sought to investigate the behavior, memory and the presence of sleep disorders in WBS and to correlate these factors with each other and with the plasma melatonin content. We used the Child Behavior Checklist for ages 6-18 (CBCL), the digit subtest of the Wechsler scale for auditory memory, the visual sequential memory subtest of the Illinois Test of Psycholinguistic Abilities (ITPA) and the Sleep Disturbance Scale for Children (SDSC). Determination of urinary aMT6s, an indirect measure of plasma melatonin content, was held for 72h by ELISA, and the analysis of the circadian rhythm of this content was performed by the Cosinor method. The results of the CBCL showed that 87% of the WBS group presented with a clinical score on the overall competence and total behavioral problems. Furthermore, the behavioral problems that were most frequently reported by parents were anxiety and problems of thought. All individuals with WBS presented with impairments in auditory memory and 47% with impairments in visual sequential memory; 65% of the WBS group presented with an indicative of at least one sleep disorder, where respiratory, initiation and maintenance of sleep (DIMS) and hyperhidrosis were the most frequent disorders. The night time aMT6s levels were lower in individuals with WBS when compared with controls; 53% of the WBS group did not present with circadian rhythm variations in aMT6s levels. In addition, there was a negative correlation between the scores of auditory memory and the total score of sleep disorders and between the DIMS and nocturnal aMT6s content. In conclusion, in the present study, individuals with WBS showed a high frequency of behavioral and memory problems, sleep disturbances and no rhythm variation in aMT6s levels. The low melatonin content may be related with sleep disorders in this population, which, in turn, can have an adverse effect on specific cognitive skills such as memory.