Twenty- five years of biochemical diagnosis of Gaucher disease: the Egyptian experience

Background: Gaucher disease is a rare multi-systemic metabolic disorder resulting from the deficiency of acid β-glucosidase activity, with consequent accumulation of glucocerebroside. Less than 15% of mean normal acid β-glucosidase activity in leukocytes is the gold standard for the diagnosis of Gaucher disease, and is generally supplemented by a massive elevation in chitotriosidase activity. We report here our experience in the biochemical diagnosis of Gaucher disease by showing the heterogeneity of the activity of enzymes over 25 years from 1993-2017, through the analysis of 5128 clinically suspected Gaucher disease cases referred to the Biochemical Genetics Department, National Research Centre, as the main reference lab in Egypt for the diagnosis of Inherited Metabolic Disorders.

Methods: Acid β-glucosidase and chitotriosidase activities were measured in all referred cases. Sphinogmylinase activity was estimated for all cases with normal β-glucosidase activity and moderate elevation of chitotriosidase.

Results: Out of the 5128 suspected cases, 882 (17%) showed a deficiency in acid β-glucosidase activity, accompanied by a raised chitotriosidase activity, ranges (213-66700 umol/l/h) and mean (7255 umol/l/h). Deficient chitotriosidase activity was found in 9 patients (1%) with low β-glucosidase. 451 cases were diagnosed with acid sphingomyelinase deficiency patients (8.8%).

Conclusion: Other biochemical markers are needed in addition to chitotriosidase for the diagnosis and follow up. Molecular testing was done to a relatively small number but needs to be done to all diagnosed patients as many mutations are known to predict the course of the disease.