[Genetics of neuronal ceroidlipofuscinoses. Aspects of genetic counseling].

Neuronal ceroid lipofuscinoses are autosomal recessive inherited disorders of neuronal cells. Neuronal ceroid lipofuscinoses belong to the lysosomal storage disorders and are characterized by accumulation of protein-lipid complexes in the lysosomal compartments of all somatic cells. This debris causes degenerative activities in the nervous system, especially in the cerebrum, the cerebellum and the afferent and efferent cranial nerves. With one exception of adult onset the disorder causes the loss of receptive, cognitive and control function in the first decade of life and an early death by the age of 20. Currently 10 loci are known which correlate to 8 genes. The genotype related phenotype and the correlated prognosis depend on the underlying gene and type of mutation. The genotype phenotype correlation is hampered by a lack of knowledge on the function of the mutant gene products. In this review we summarize the known genetic data on neuronal ceroid lipofuscinoses and comment on therapeutic approaches.