Developmental and learning problems have been reversed in mice with a condition that mimics Down’s syndrome.
Scientists at the National Institutes of Health in Maryland genetically engineered mice to give them an extra chromosome 16.
The genetic alteration produces similar clinical problems to those seen in people with Down’s syndrome, a condition caused by having an extra chromosome 21.
The scientists injected two genes into a separate group of mice while they were still in the womb. The genes lead to the production of proteins usually made by specific brain cells called glial cells which have been found to malfunction in patients with Down’s syndrome.
The proteins were then extracted and given to the first group of mice orally for four days, after which the mice performed just as well in problem solving tests as mice with normal genetics.
Around 750 babies are born with Down’s syndrome in the UK each year. The condition is associated with reduced cognitive ability and physical growth but symptoms can vary significantly between patients.
This variation is thought to be caused by complex interactions between the extra genetic material and the environment a baby grows up in.
Congenital heart defects, recurrent ear infections and thyroid gland dysfunction are also commonly associated with the syndrome.
Although results have been encouraging, the technique carries too many risks for the team to attempt the treatment in children. The next step is to test the procedure on adult mice.
Craig Heller, co-director of Stanford University’s Down Syndrome Research Centre in California, says the study does make one thing clear: “Learning disabilities that were considered permanent are treatable.”
Image by Steve Berger
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