• INTRODUCTION
    • Perthes disease radiography can mask other diseases. Properly observing the X-ray and changes in other joints helps to discard Perthes-like conditions. Association with changes in other systems, as well as the pathological history and even the examination of family members can help diagnose early attenuated cases of rare diseases.
  • CASE PRESENTATION
    • The case of a girl with hip pain, limp and doubtful radiographs is presented. Perthes disease was diagnosed elsewhere and physical therapy and analgesics were prescribed. As a second opinion, family look for another orthopedic physician, who looks beyond hip pain and limp. Full body X-rays are suggestive of skeletal dysplasia. Metabolic disease diagnosis is suspected with pathological history of the younger brother, with repetitive respiratory infections, as well as abnormal X-ray panel. Multiple dysostoses in both patients are demonstrated. The above findings help to diagnose Morquio disease in an attenuated variant after molecular examinations.
  • CONCLUSION
    • Early diagnosis in progressive diseases is essential to avoid progression to multi-organ deterioration. It is important that physician become familiar with habitual characteristics of Perthes disease on the pelvis radiograph, in order to unsure the error in the diagnosis.