Down syndrome mouse created

US scientists have created the first mouse model of Down syndrome (DS), a condition that affects one in 700 human babies. People with DS have an extra copy of human chromosome 21, and the mice have three copies of the corresponding mouse chromosome regions.

The researchers, speaking at the American Association for the Advancement of Science say their mouse model of DS has already revealed unknown features of the human version. 'Nobody knows exactly why having too much of a chromosome would lead to the developmental problems you see with Down syndrome' said Professor Roger Reeves of Johns Hopkins University, Baltimore. 'We believe this model will explain that in a way we couldn't before.'

Using a laser-equipped, 3D-measuring microscope, the scientists looked at the shape of the DS mouse skull and compared the results with the skull and facial shape of people with DS. 'We found an absolute correspondence' said Professor Reeves. 'The changes in the mouse face are in the same bones, in the same patterns, as in humans.' The team believes the mouse model will help reveal genes that affect the development of the face and skull, as well as shedding light on DS.

The research may eventually pave the way for new therapies for DS. Professor Reeves said there was great interest in using stem cells, to grow new nerve and other cells to 'tone down' the problems caused by the syndrome. Another approach may be to use gene therapy to counter the effects of the extra chromosome 21 genes.