Progress in neuropathology of the neuronal ceroid lipofuscinoses

Since the last, 6th, International Congress on Neuronal Ceroid-Lipofuscinoses, neuropathological advances in neuronal ceroid lipofuscinoses (NCL) have been made in several areas: (1) In adult NCL (ANCL) lipopigments have now been repeatedly confirmed to contain subunit c of mitochondrial ATP synthase and even sphingolipid activators (saposins). ANCL lipopigments have also been confirmed in extracerebral tissues including skin, skeletal muscle, and spleen, but not yet lymphocytes (2). Among circulating blood cells not only B cells and subclasses of T lymphocytes, i.e., CD4 + , CD8 + , and CD56 cells, but also monocytes have been found to contain NCL lipopigments, indicating that this precursor cell in the digesting macrophage system also has an impaired metabolic catabolism for lipopigments (3). Immunohistochemical studies indicate that microglial reaction in NCL brain is limited to resident microglia without contribution by circulating monocytes (4). The granular osmiophilic deposit (GROD) type of NCL has now been established not only in infantile, but also in late-infantile, juvenile, and protracted-juvenile NCL (5). A European Tissue Registry established within the framework of a European Concerted Action on Neuronal Ceroid-Lipofuscinosis may form the basis for additional collaborative studies on NCL, including both biopsy and autopsy tissues.