Niemann-Pick's and Gaucher's diseases.

A short account is presented of the evolution of knowledge concerning Niemann-Pick's and Gaucher's diseases, two autosomal recessive genetic disturbances of lysosomal storage function. This culminated in the intriguing realisation, arising from mounting clinical and molecular evidence, that glucocerebrosidase mutations constitute the most common risk factor for Parkinson's disease identified to date.