Inclusion criteria:  Patient under the age of 18 years Patient with unexplained SMG (SMG defined as a palpable spleen, already known or discovered for the first time) and who has undergone tests to eliminate obvious causes of SMG  Exclusion criteria:  Patient with any obvious cause of SMG as described by clinical examination and/or lab or imaging test available in medical records and/or having been diagnosed with any of the following conditions:  hemolytic anemia hematological malignancy portal hypertension infectious disease associated with SMG (Cytomegalovirus, Epstein Barr virus, leishmaniasis or other obvious infectious cause revealed by the medical history)  The above information is not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.