Pathophysiology of Rett syndrome.

Rett syndrome is a distinct clinical entity with an unknown cause. In previous publications we stressed the age related sequential appearance of pathognomonic symptoms of Rett syndrome and suggested the early central monoaminergic deficiency disorder as the pathophysiology. In this report we present a series of cinefilms made of one patient at different ages which clearly show the age dependent changes of motor disturbances. Furthermore, the record of sleep-wakefulness rhythm and the series of polysomnography of another patient who was on L-DOPS are presented. The results of sleep studies again confirm the early involvement of the noradrenergic and serotonergic systems and relatively early development of postsynaptic supersensitivity of the dopaminergic system. The possibility of the involvement of the cholinergic system is also suggested. The summary of the sensory evoked potentials (SEP) performed on six patients is also presented and the pathomechanism of cortical involvement is discussed. Based on these new and past findings, we confirm our speculation on the pathophysiology. The basic mechanism is probably the deficient states of the monoaminergic systems occurring at a very early developmental stage. These derangements occurring at an early stage cause serious abnormality in the higher centers during development. The striking age dependent clinical manifestations and measurable physiological parameters are the reflexion of the underlying patho-physiology of Rett syndrome.