Stanford, Calif. - Researchers at the Stanford University School of Medicine and Lucile Packard Children's Hospital have identified one possible cause of mental retardation in Down syndrome. The culprit is a gene that, when overexpressed, causes neurons responsible for attention and memory to shrivel and stop functioning normally. The finding offers the first glimmer of hope that doctors could one day interfere with or even reverse the cognitive decline that frequently affects those with Down syndrome in middle age.
"We may now have the opportunity to make a big difference in people's lives," said neurologist William Mobley, MD, PhD. "If we can decrease the expression of this gene we may be able to provide something more than supportive care to people with Down syndrome."
Mobley, who is the John E. Cahill Family Professor at Stanford's School of Medicine and director of Lucile Packard Children's Hospital's Down Syndrome Center, is the senior author of the research, to be published in the July 6 issue of Neuron. He is also the director of Stanford's Neuroscience Institute.
More than 300,000 people nationwide have Down syndrome, which is caused by an extra copy of chromosome 21, giving them a total of three. Although it is the leading cause of mental retardation in the country, little research has been conducted at the molecular or neurological level to understand and explore potential therapies for its symptoms. In addition to dealing with early cognitive difficulties, childhood heart disease and leukemia, most people with Down syndrome develop Alzheimer's disease by the age of 40.
"Down syndrome results in an extraordinarily complex constellation of symptoms," said lead author and senior research scientist Ahmad Salehi, MD, PhD. "We've done what many people thought was impossible: We've dissected it genetically to correlate one of the most troubling symptoms - cognitive dysfunction - with one particular gene
Contact: Robert Dicks
Stanford University Medical Center