Juvenile idiopathic arthritis is an inflammatory disease with various onset-forms which can sometimes be difficult to distinguish from genetic inflammatory/rheumatoid-like osteoarthropathies. In this report, we describe two boys with severe chronic arthralgia, stiffness and swelling of joints, motor weakness and joints contractures evolving despite immunosuppressive treatments and for whom all biological and molecular exams failed to identify a prompt diagnosis. Some findings also overlap with pseudorheumatoid dysplasia but WISP3 gene molecular analysis failed to identify any mutation for both patients. Therefore, we propose that these boys show a clinical entity distinct from the actually known genetic inflammatory/rheumatoid-like osteoarthropathies. © 2012 Wiley Periodicals, Inc.