What should you know about hereditary Perthes disease?

Perthes disease affects the developing hip when the femoral head receives reduced blood flow. In most families, there is no clear inheritance pattern that can predict which child will develop it. A history of the condition in a parent, sibling, or other relative may be worth recording, but it is only one part of the medical history.

A child with a family history is not diagnosed from that history. The clinician looks for a limp, hip or thigh discomfort, reduced hip rotation, and changes on imaging. Conversely, a child without a known family history can still develop Perthes disease.

Share the family history at the appointment, including which relative was affected and whether the diagnosis was confirmed. Do not wait for genetic certainty if a child develops a persistent limp or restricted hip movement. Once diagnosed, keep monitoring visits and follow the advice on walking, sport, rest, and exercises. Paediatric physiotherapy may help maintain useful movement; the team can explain whether an operation such as osteotomy is relevant.

Seek urgent care for sudden inability to bear weight, severe pain, fever with a hot or swollen joint, or a child who appears very unwell. Arrange prompt review for a new limp that persists or gets worse. See [Limping](/symptoms/limping/) for related guidance.

Ask whether the family history changes follow-up, whether siblings need any symptom checks, and which signs should trigger an appointment. You can also ask how movement will be protected and when treatment options would be reconsidered.