the-BA : Facing up to genetics

By Wendy Barnaby

Children with rare genetic conditions may be more quickly diagnosed as a result of a computer programme which scans the shape of their faces.

“Many genetic conditions affect the development of the face,” Professor Peter Hammond from the UCL Institute of Child Health will tell the BA Festival of Science on Monday.

“We all recognise the characteristic face of a Down's syndrome child, but there are other, rarer conditions. Williams syndrome, which affects one in 10,000 to 20,000 births, results from an alteration on chromosome 7. It makes the temples narrower, the mouth fuller and the jaw smaller – as well as producing super-friendly children.”

Professor Hammond has created software which compares a 3D picture of the child's face with other faces, to see which abnormal face it fits most closely. The image of the abnormal face is a composite of between 30 and 150 children with that condition.

Each image contains 25,000 or so points on a face surface, capturing even the most subtle contours in 3D.

The new method will help train doctors to recognise rare disorders. Trainee clinical geneticists in Cambridge will benefit from it for the first time in January.

“The software can also reduce the number of possible genetic tests given to each child,” says Professor Hammond. “Each test costs between £500 and £1,000, so this will save money for the NHS.”

“It will also mean earlier diagnosis, more appropriate monitoring and perhaps educational intervention or behavioural therapy. And parents will know earlier of risks to future children.”

There are over 700 genetic conditions associated with characteristic facial features. Fragile X, the most common form of inherited mental impairment, affects one birth in 4,000. Children with the condition have longer, narrower faces, with bigger jaws and ears that stick out very slightly.

Smith-Magenis syndrome affects one birth in 25,000. It produces a nose with a flat bridge and an upper lip that looks as though it's been lifted up from the inside. Children with this condition can be aggressive and self-harming. They sleep in the daytime and are awake at night.

The new software has identified Fragile X faces with an accuracy of 92%; Smith-Magenis syndrome at 91% and Williams syndrome at 98%.

Professor Hammond envisages a future in which doctors take 2D pictures of children's faces, email them to a specialist centre which converts them to 3D and compares them with model faces, and emails back suggestions about which genetic tests to do first.

“The price of the cameras is coming down but they still cost between £10,000 and £20,000,” he says.

Read more news coverage in the Guardian, BBC News, the Scotsman, the Telegraph and DailyIndia.com. Watch the video highlights at BBC News.

This year’s BA Festival of Science is organised by the BA (British Association for the Advancement of Science) in partnership with the University of York, Science City York and the City of York council. It is supported by the Department for Innovation, Universities and Skills, BP and Yorkshire Forward.