Summary
Neuronal ceroid lipofuscinoses (NCL or CLN) are a mixed group of genetic progressive storage disorders of the brain and eyes. The overall incidence of NCL in Europe, North America, and some other countries is as high as 1 in 12,500. Manifestations usually begin during childhood and adolescence, but very rare cases of onset in young adults have been reported. These heterogeneous disorders, genetically classified as CLN1 to CLN8, share similar symptoms and signs such as retinopathy with loss of vision, epilepsy, dementia, and accumulation of unusual waxy material termed ceroid lipofuscin (autofluorescent lipopigments) in brain and other tissues. The mode of transmission is mostly autosomal recessive. Their pathophysiology is poorly understood and involves the combination of an intracellular storage process and a progressive loss of nerve cells. Two NCL disorders are caused by deficient lysosomal enzymes, namely palmitoyl-protein thioesterase in CLN1 and tripeptidyl-peptidase in CLN2. In some others, it has been found that membrane proteins with unknown function are deficient. The genetic defect can be identified in most cases and forms the basis for family counseling and prenatal diagnosis. All NCL disorders remain untreatable, progress relentlessly, and usually lead to early death. *Author: Prof A. Kohlschütter (January 2004)*.
