Gaucher disease (GD) is characterized by a deficiency in lysosomal glucocerebrosidase, resulting in a multisystemic disease with substantial variability in clinical manifestations, disease progression, and treatment response. This is the first study in Canada that examines the epidemiological profile of Gaucher patients, mapping out the GD clinical spectrum in the ethnically diverse province of Ontario.Study found a prevalence of 1:155,367 (1:9,853 for Ashkenazi-Jews) type 1 GD adults in Ontario. Splenectomy was associated with improved thrombocytopenia, worsened hyperferritinemia and bone pain, but no effects on anemia, bone mineral density or bone crises. Compared to the non-treatment group, a higher proportion of patients who received enzyme replacement/ substrate reduction therapy (ERT/SRT) presented with anemia, hepatomegaly, bone pain, and bone crises at baseline, suggesting that these presentations may be predictive of subsequent need for treatment. ERT/SRT were effective in improving all hematological, visceral, and skeletal manifestations (except bone mineral density), whereas the non-treatment group remained clinically stable over time (10.88 years) without significant disease progression -thus early use of ERT/SRT may not be necessary in all patients. This comprehensive analysis summarizes the genotypic and phenotypic heterogeneity of GD, serving as a comparative resource for optimization of care for adult patients.