dysplasia epiphysealis hemimelica (MONDO_0007489) (DEH), or Trevor's disease, is a rare condition that most commonly affects the epiphysis (the end) of long bones in children. Early diagnosis and treatment are necessary to prevent joint dysfunction and deformity and may be surgical or non-surgical depending on the location and the symptoms. Due to the progressive nature of this disorder and the chance of worsening deformity, patients should be followed until skeletal maturity. The cause of dysplasia epiphysealis hemimelica is not known. Also known as: Trevor disease.