Gaucher disease is a disease of overload lyosomale which we often met since a score of years. Since 1980 we had to answer several requests for diagnosis of this metabolic disease. Requests emanating primarily from paediatric services. Twelve cases were confirmed within sight of measurement of the intra-leucocytic activity of the beta-glucocerebrosidase, enzyme intervening in the catabolism of the sphingolipides. We report here our experiment in the biochemical diagnosis of Gaucher disease by showing mainly the variability and the extreme heterogeneity of the activity of the beta-glucosidasic during practised measurements. In addition, we expose the problems of diagnosis etiologic which certain patients raise in front of the discordances between the measured enzymatic activity and clinical signs of the disease of left-handed person. In addition, we develop the biological parameters useful to proportion for the monitoring of the treatment which is finally available in our country.