Diagnosis can be made if 1+2 or 1+3+5+6 or 1+4+5+6 are met.

Knee involvement is most common clinically, with early symptoms of pain and stiffness, alternating between unilateral or bilateral, often occurring when going up and down stairs, worsening with activity, and relieving with rest. Physical examination may show joint swelling, tenderness, crepitus, and varus deformity of the knee. A few patients may have muscle atrophy around the joint, mostly due to disuse.