Microvascular abnormalities in Rett syndrome.

Rett syndrome (RTT) is a post-natal neurological disorder that represents the second most common cause for mental retardation. The presence of cold hands and feet, and blue, a feature frequently observed in these patients, is one of the non-neurological phenotypes that characterizes RTT, up to now not well explained. We have performed videocapillaroscopy in subjects affected by Rett syndrome. We have observed ramified and bushy capillaries, characteristic features of neoangiogenic capillaries, dilated capillaries and an irregular and chaotic microvascular pattern. To quantify these features and to evaluate the microvascular pattern complexity, we have performed a fractal analysis. Fractal dimension and Lempel-Ziv indexes resulted higher in Rett females than in age-matched healthy females (p < 0.001; p < 0.001). Our findings indicate the presence of previously unrecognized microvascular abnormalities in Rett syndrome.