We also observed significant differential enzyme activity of GCase or for the β-glucocerebrosidase:α-hexosaminidase ratio in subjects carrying GBA mutations classified phenotypically (as in Gaucher disease) as ‘severe’ type (e.g. 84insGG, L444P) (p<0.01) compared to subjects carrying GBA mutations classified phenotypically as ‘mild’ type (e.g. N370S, R496H) (p<0.05) or of unknown phenotypic effect (E326K, T369M) (p<0.001) compared to controls (Fig 1). The gene discussed is GBA1; the disease is Gaucher disease.