What should you know about Perthes disease and genetics?

Perthes disease involves temporary disruption of blood flow to the femoral head during childhood. Its cause is often not clear, and it is not usually passed through a family in a predictable pattern. A relative with Perthes disease may be relevant background, but it does not establish that another child has the condition or that a child will develop it.

Clinicians may ask about relatives with childhood hip problems and about the child’s general health. They still rely on symptoms, hip movement, walking pattern, and imaging rather than a genetic label. A limp can have many explanations; it should be assessed on its own clinical findings.

Tell the orthopaedic team about any family history and bring details of when relatives developed symptoms, if known. Watch for a persistent limp, reduced hip movement, or pain in the hip, thigh, groin, or knee, and arrange an assessment if these appear. If Perthes disease is diagnosed, follow the activity plan and attend monitoring visits. Paediatric physiotherapy may support movement while the hip is protected.

Get urgent medical advice if a child suddenly cannot walk, has severe pain, develops fever with a hot or swollen joint, or looks acutely ill. A gradually worsening limp also merits timely review, whether or not there is a family history. More information about this symptom is available under [Limping](/symptoms/limping/).

Ask whether the family history changes the assessment, whether any testing is appropriate, and which symptoms should prompt review of siblings. Discuss activity limits, physiotherapy, imaging follow-up, and when an operation such as osteotomy might enter the conversation.