A Significant Problem in Rett Syndrome 'Autonomic Dysfunction'

Objectives:Rett syndrome (RTT) is a severe X-linked neurodevelopmental disorder.Irregular breathing attacks in wakefulness, which occur due to the fact that brain stem development is interrupted in the neonatal period, cause discomfort to the patient and caregivers. Low cardiac vagal tone at rest and poor vagal response to hyperventilation and breath-holding are the result of inadequate parasympathetic control in the immature brainstem. Evaluating brain stem functions in RTT requires multidisciplinary electrophysiological studies. The detection of autonomic dysfunction as a consequence of Holter-ECG, polysomnography (PSG),and video-EEG tests, as well as treatment techniques in four patients with RTT, were discussed in this study. Case Reports:The first case is a female patient with neurodevelopmental retardation who was previously undiagnosed with RTT and experienced many episodes of sudden cyanosis throughout the day.The video EEG did not reveal any epileptic activity. In PSG data during wakefulness, while there was breath-holding and a decrease in oxygen saturation, there was no change in heart rate. The other three patients were genetically diagnosed with RTT,and two of them experienced breath-holding attacks and the other had hyperventilation attacks. Neurophysiological testing was performed on these patients, and autonomic dysfunction was detected. The patients were started on propranolol medication, and their breath-holding attacks improved significantly. Discussion:Brain stem immaturity and autonomic dysfunction, which are prevalent and life-threatening in RTT patients, impair both the family's and the patient's quality of life. This condition, which might lead to beneficial medical treatment outcomes, should be investigated as a multidisciplinary approach in the follow-up of RTT patients.
Keywords: Rett Syndrome, Autonomic Dysfunction, Breath-holding, Electrophysiology