Scientists have made a breakthrough in the study of Down's syndrome after discovering a method to prevent the chromosomal disorder in the womb itself.

In the study on mice, the scientists observed that when foetal mouse pups that had a syndrome similar to Down's were treated with nerve-protecting chemicals, some of the developmental delays that are part of the condition were removed.

Kids with Down's have an extra copy of chromosome 21, while mice engineered to have a similar condition are given an extra copy of a segment of chromosome 16.

In both species, the development of certain motor and sensory abilities is delayed. These "trisomic" individuals may also have learning difficulties and symptoms of Alzheimer's later in life.

The scientists found that inhibition of neurotransmitter GABA in trisomic mice can improve cognition and this could eventually be used in children.

In fact, many researchers have claimed that treating Down's before a child is born would improve cognitive potential too.

Earlier studies both of people with Down's and trisomic mice revealed malfunctions in glial cells - brain cells that regulate the development of neurons by releasing certain proteins. The aberrant cells produce less of these proteins than normal. And adding segments of some of these proteins - known as NAP and SAL - to cultured neurons from people with Down's, which would otherwise degenerate, seems to protect the neurons.