ELECTRON-DENSE LIPIDIC CAPILLARY DEPOSITS IN RETT SYNDROME

Conjunctival, muscle, and peripheral artery biopsies were examined by light and electron microscopy in a patient with clinically diagnosed Rett syndrome. In capillaries, amorphous and membranous electron-dense deposits were observed (a) endoluminally attached to endothelial cell membranes, (b) within junctional clefts of adjacent endothelial cells, and (c) at abluminal sites of endothelial cells. In addition, electron-dense deposits layiisolated or inside multivesicular bodies in endothelial cells and pericytes. These findings have not been reported before in Rett syndrome. They were not seen in agematched normal or pathological control cases and are suggested to indicate deposition of an as yet unknown lipidic plasma component possibly in association with impairment of the blood-tissue barrier. © 1990 Springer-Verlag.