A way to help diagnose rare genetic disorders by the appearance of a child's face has been developed to the point where it can train junior doctors.
Oscar Wilde said that a man's face is his autobiography. Now it seems that it can also help to reveal the precise genes that, when damaged, cause severe developmental disorders so that diagnosis can be made earlier, Prof Peter Hammond of the UCL Institute of Child Health will tell the nation's biggest annual general science meeting this week.
The public easily recognise individuals with Down syndrome, but there are over 700 of the 5,000 documented genetic conditions that involve unusual and often subtle changes to the face.
Affected children may have eyes set further apart, ears set lower on the head, a shorter nose, fuller lips, a larger tongue or a mouth narrower than in children of typical development, he said.
Last Mod: 10 Eylül 2007, 16:39
These are often obvious to experienced doctors, who have had a long time to become familiar with possibly a handful of cases they see over a career, but to junior doctors the differences are hard to link with particular conditions.
The new method compares a child's face to similarly aged groups of individuals with known conditions and selects which condition looks the most similar. In order to do this, collections of 3D face images of children and adults with the same genetic condition had to be gathered, as well as controls or individuals with no known genetic condition. It has already been used in research projects and to help diagnose a small number of difficult cases.
The method also revealed "unusual facial asymmetry" in children with autism spectrum disorder reflecting a lopsided feature of the brain, he added. A part of the brain, called the right frontal pole, is known to be larger than on the left side in children with autism and this may be linked with a raised spot on the right side of the forehead.
The insights have come from a project in which Prof Hammond spent seven years travelling worldwide to scan affected children to hone computer software that compares the faces of undiagnosed children with those with genetic disorders that affect their development and especially their face.
Now the software can recognise the facial characteristics of 10 or so conditions with a 90 per cent success rate or better he will tell the British Association's festival of science in York today.
If, in a difficult case, the software can narrow down the possibilities to conditions with similar facial features, a doctor can then undertake further examinations and DNA tests, if they exist, to determine the diagnosis. Testing for fewer conditions will save money, time and reduce the amount of stress the child and the parents are put under.
"This could reduce the amount of testing and associated stress for the child, and maybe even save money," he will tell the British Association, adding that genetic testing can cost up to £1000. " It could also speed up the diagnostic process and help reduce the anxiety of parents who need genetic counselling."
Prof Hammond said: "Delay in diagnosis causes anxiety to parents who need advice on risks to their future children. Moreover, delay may defer important medical treatment or behavioural training that could improve the prognosis for affected children.'
Cambridge University, 40 junior doctors will test if these visual training aids help improve their skills in recognising the facial characteristics of a range of conditions.
He paid tribute to the co-operation of the families of affected children and the support of organisations such as the Fragile X Society and the Williams Syndrome Foundation.
In the longer term, these 3D scan methods combined with the revolution in personal genomics - reading an individual's entire DNA code - will help to reveal the DNA that controls why one person looks different from another, as the face develops under the influence of many genes and in close synchronisation with the development of the skull and brain.
William's syndrome. First described by the eponymous heart specialist in new zealand in 1961, williams syndrome affects about one child in 20,000 and is caused by the loss of genes lying on one of the pair of chromosome 7 in cells.
Those with the disorder are often first diagnosed because they have cardiovascular problems. They typically develop good speech but have difficulties in tasks that require them to understand how things are related in space, such as construction with building blocks. However, they are acutely sensitive to sound, loving and sensitive to the feelings of others, with a happy disposition. "They are delightful to be with," said Prof Hammond. The visuals derived from his software show that affected children have narrower temples; and a more upturned nose and fuller lips, for example.
Smith-Meganis syndrome. Affected individuals are cognitively impaired. They can sometimes be self harming and often have an "inverted sleeping pattern", sleeping in the day and remaining awake at night. The visual shows the bridge of the nose is flat and the upper lip has an unusual shape.
Jacobsen syndrome. Affects one birth in 100,000 and causes learning difficulties, heart defects, eye problems and a bleeding disorder. Here the visual shows the eyes are further apart than usual.
Fragile X syndrome. One male in 4000 is estimated to have this syndrome, which is the most common form of inherited learning disability. The visual shows how the face can be longer and narrower, the ears can be more protruding and the jaw larger than children of a similar age of typical development. But these differences are usually very subtle.