3-D facial images of children can reveal genetic disorders

The facial features of children can be analysed in three dimensions to help doctors assess whether a child is suffering from one of the many hundreds of rare genetic disorders that can affect the development of the face and brain.

A scientist has developed a way of feeding 3D images of a child's face and head into a computer so that the software can analyse the relative position of all the facial features and compare them against a database of genetic disorders.

At present, specialists diagnose the many thousands of childhood genetic diseases with the help of blood tests, but many conditions are so rare that there is a risk of inexperienced GPs not realising what is affecting their patient, said Professor Peter Hammond of the Institute of Child Health at University College London.

"There are 5,000 documented genetic conditions in the medical literature and of those about 700 involve the face, so potentially this technique could be used for 700 or so conditions," Professor Hammond said. "By looking at the face you can associate it with the genes. The face and the brain develop very closely so the genes that affect the face often affect the brain," he said.

Many genetic disorders result in subtle changes to the face that may not be obvious to less experienced doctors. The eyes may be slightly further apart than normal, the ears could be set lower down or the lips may be slightly more protruding.

Professor Hammond has built up a database of the facial characteristics of individual disorders based on real patients to devise an average-looking face for each illness. He has also done the same to form the average face for healthy children.

The computer software has already shown itself capable of correctly identifying half a dozen rare genetic disorders based on facial features with an accuracy of between 92 and 98 per cent. It would provide an invaluable tool for training medical specialists as well as helping GPs who may never have seen the disorder in question, Professor Hammond said.

"Delay in diagnosis causes anxiety to parents who need advice on risks to future children. Moreover, delay may defer important medical treatment or behavioural training that could improve the prognosis for affected children," he said.

"You can look at the face to help screening and reduce the number of possible genetic tests that would have to be undertaken. So for the NHS, the benefit could be more focused genetic testing because these tests can cost as much as £500 to £1,000 and they take time.

"This is not diagnosis. The diagnosis is done by a clinician and a molecular geneticist doing the genetic testing. This is just about recognising the facial features," he added.

The system is still under development, but it may prove especially useful for doctors who deal with patients from ethnic minorities, where it may be even more difficult for an inexperienced doctor to assess abnormal facial characteristics, said Professor Hammond, who will present his finding today at the British Association's Science Festival in York.

Each 3D image contains information on about 25,000 different points on the surface of a face.