What are the symptoms? Fibular hemimelia (FH)In FH, the fibular (calf-bone) fails to develop in part or in whole. Usually, only one leg is affected and it is usually the right. This can result in a range of problems, including: mild bowing of the legthe affected leg may be shortersoft tissues can be affected, including muscle and ligaments attached to the fibula that stabilise the knee jointknee instability, which can lead to a ‘knock-knee’ appearancethe ankle may be unstable with a reverse ‘club-foot’ appearance. Tibial hemimelia (TH)In TH the tibia, one of the long bones in the leg, fails to develop in part or in whole and can occur in one or both legs. Symptoms include: deficiency of the ligaments that support the knee. The knee can have a ‘knock-knee’ appearance or be hypermobile (move around too much)sometimes it can be difficult to straighten the kneeas the inner side of the ankle is usually missing the foot may be pointing downwards and inwards, often in a fixed position known as clubfootthere may be extra toes or the foot may have a cleft/split. Radial hemimelia (RH)In RH, also known as radial clubhand, the radius (one of the two large bones of the forearm) fails to develop normally either in part or in whole and this can affect one or both arms. Symptoms include: shortened forearm and the wrist in a fixed bent position with the hand lying to the thumb-side of the wristthe thumb may be small or absent, with one or two fingers on the hand missingsoft tissues such as muscles and ligaments may be affectedthe ulna may overgrow or be bowed and the shoulder may be affectedrarely, there are cardiac (heart), kidney, trachea (windpipe) and oesophagus (the tube that food goes down to the stomach) problems. The condition may be linked with other disorders such as TAR syndrome or Fanconi anaemia. Ulna hemimelia (UH)In UH, also known as ulnar club hand, the ulna bone of the forearm fails to develop properly. In most people, just one arm is affected and symptoms include: the position of the hand tends to drift to the little-finger-side of the wrist and sometimes fingers may be short or absent.there may be synostosis (where the radius is fused to the ulna). Rarely, there are associated abnormalities of the femur (thigh bone), fibula or shoulder blade. What are the causes? Most cases of hemimelia occur for no apparent reason. Some genetic mutations (changes in DNA) have been identified for some types of hemimelia such as those associated with TAR syndrome or Fanconi anaemia. Families that are worried about genetic problems causing hemimelia should seek advice from a geneticist. Some medications have been linked with hemimelia, for example insulin with FH. It is thought that sometimes an insult (damage to the baby) in the early weeks of development in the womb can cause hemimelia. How is it diagnosed? This is based on examination by a doctor and X-rays. In rare cases, tests may find a genetic problem causing the hemimelia. How is it treated? Treatment will vary according to how severely the individual is affected and an orthopaedic specialist will advise on what treatment is necessary. Non-surgical treatments may be used instead of surgery, or before and after surgery, to help reduce the symptoms of hemimelia. Initially treatment involves bandaging or strapping and gentle manipulative exercises, usually under the supervision of a physiotherapist. Depending on how severely the limb is affected, surgery may be necessary to improve the quality of life of the person affected. Surgical removal of extra toes will help for shoe comfort or fitting of an orthotic limb (artificial leg). Leg lengthening if a limb is shortened may also be carried out. In upper limb abnormalities correcting the skewed wrist position may be beneficial. Inheritance patterns and prenatal diagnosis Inheritance patternsNot typically seen. Some syndromes demonstrate an inheritance pattern such as TAR syndrome (see entry). Prenatal diagnosisAn anomaly ultrasound scan at 20 weeks may show up limb abnormalities. Is there support? There is no support group for Hemimelia in the UK. Families can use Contact’s freephone helpline for advice, information and, where possible, links to other families. To meet other families with disabled children, join Contact’s closed (private) Facebook group.