Gaucher disease type 1 is a lysosomal storage disease with hematological and bone involvement and visceromegaly. Until about twenty years ago it was commonly accepted that neurological involvement could only occur in the most severe forms, type 2 and type 3 Gaucher disease. This principle has been questioned since the first series of patients with Parkinson's disease and Gaucher’s disease were described. It was then clearly demonstrated that the GBA1 mutation, which is responsible for Gaucher’s disease, was also responsible for Parkinson's disease. Glucocerebrosidase, which is active in the lysosome and deficient in Gaucher’s disease, is closely correlated with the accumulation and aggregation of synuclein found in Parkinson's disease. Improving knowledge on rare diseases has an impact on the knowledge of more frequent disease. In this work, we highlight some of the most recent discoveries on Gaucher’s disease through the description of new clinical manifestations, the trend to personalized treatment, and the discovery of new complications. Through these different manifestations associated with Gaucher's disease, we show how an ultra-rare disease can help to better understanding of a very common one and can lead to other therapeutics. As a consequence, glucocerebrosidase represents a promising target to develop further disease modifying treatments in Parkinson’s disease.