beta(1)-adrenergic antagonists improve sleep and behavioural disturbances in a circadian disorder, Smith-Magenis syndrome

Smith-Magenis syndrome (SMS) is a clinically recognisable contiguous gene s yndrome ascribed to interstitial deletions of chromosome 17p11.2. Patients have a phase shift of their circadian rhythm of melatonin with a paradoxica l diurnal secretion of the hormone. Serum melatonin levels and day-night be haviour were studied in nine SMS children (aged 4 to 17 years) given acebut olol, a selective beta (1)-adrenergic antagonist (10 mg/kg early in the mor ning). Cardiac examination, serum melatonin, motor activity recordings, and sleep diaries were monitored before and after drug administration. The pre sent study shows that a single morning dose of acebutolol suppressed the in appropriate secretion of melatonin in SMS. A significant improvement of ina ppropriate behaviour with increased concentration, delayed sleep onset, inc reased hours of sleep, and delayed waking were also noted. These results su ggest that beta (1)-adrenergic antagonists help to manage hyperactivity, en hance cognitive performance, and reduce sleep disorders in SMS.