· Goldenhar syndrome is a rare condition that afflicts around one baby in 500,000. There are thought to be only around 75 people who were born with it in the UK.

· It is named after the Swiss ophthalmologist Maurice Goldenhar who wrote a paper on it in 1952, although the earliest medical description of the characteristics is thought to have been given by the 19th century German physician Ferdinand von Arlt.

· The syndrome embraces a wide range of problems, but most typical is the malformation of one side of the face. One ear is missing or underdeveloped - sometimes the ear canal is missing - and the baby will be deaf on at least that side. The cheek, face muscles and jaw on the same side are also underdeveloped and the eye can be affected. In the child at the centre of the legal row, the eye is missing, but some children have a small eye or have sight problems on that side.

· When only the ear, cheek and jaw have not fully developed, the condition is known as hemi-facial microsomia. Goldenhar syndrome is diagnosed when there are additional problems, such as with the vertebrae, or affecting the heart or kidneys.

· Children with Goldenhar syndrome are usually of normal intelligence, although 13% have learning difficulties which are usually due to deafness. There may also be speech and swallowing problems.

· Nobody is sure what causes the syndrome. Although there have been cases among siblings, on the whole it does not run in families. Various environmental causes have been suggested but nothing has been proven. Children with Goldenhar syndrome have been born to US veterans of the Gulf war, who are now suing for compensation.