Objective: To assess prevalence of Gaucher disease (GD) diagnosed in pediatric patients presenting with unexplained splenomegaly (SMG) after exclusion of first intention-diagnoses (e.g. portal hypertension, haematological malignancy, hemolytic anemia, infection) based on clinical examination and routine biological tests (full blood count, reticulocytes, liver tests, abdominal ultrasound, Coombs test and Epstein Barr virus serology). Secondary

Objectives: * To describe the rate of each identified disease category and the rate of patients with no final diagnosis at the end of the study in pediatric patients with unexplained SMG after exclusion of first intention diagnoses * To describe the characteristics (clinical, lab, genetics) of all pediatric patients included in the study and to describe the characteristics subdivided by identified disease category and absence of final diagnosis at the end of the study