Reference intervals for lysosomal glucocerebrosidase activity in the healthy population

Reference intervals, representing the normal range of values across age and gender groups, are essential for determining whether parameters from an individual are within physiological limits or not. Lysosomal glucocerebrosidase (GCase) activity has diagnostic relevance for Gaucher's disease (GD); it is also important in Parkinson's disease (PD) and other neurodegenerative disorders, particularly for assessing lysosomal functions. Although accurate laboratory tests are available for GCase, the absence of established reference intervals limits their application in clinical diagnostics and research. In this study, we measured GCase activity using leucocytes from healthy blood donors (n = 530) belonging to the 18-65 years age group. This study establishes a reference range for GCase activity in the healthy population, with a median of 2.29 nmol/10⁷cells/h (Inter-quartile range: 1.21-4.01; 95% reference interval of 0.093-8.945 nmol/10⁷cells/h). There was a slight decline in GCase activity beyond the age of 45 years. Females displayed higher GCase activity compared to males among all age groups. Haemoglobin, blood group and body weight showed no significant correlation with GCase activity. Our results increase the clinical and research utility of GCase assay, relevant to the screening of individuals with suspected lysosomal storage disorders and research in PD and other neurodegenerative conditions. The availability of reliable reference intervals may also facilitate a better understanding of lysosomal biology in health and disease.