Gene may cause retardation of Down’s syndrome

	Tweet

A gene mutation that shrinks brain cells may be responsible for the mental retardation of Down’s syndrome, U.S. researchers reported on Wednesday.

The finding suggests there may be a way to interfere with or even reverse the additional mental decline often seen as people with Down’s syndrome age. The finding, published in the journal Neuron, also may apply to Alzheimer’s disease, the researchers said.

“If we can decrease the expression of this gene we may be able to provide something more than supportive care to people with Down’s syndrome,” said neurologist Dr. William Mobley of the Stanford University School of Medicine and Lucile Packard Children’s Hospital in California. Reducing gene expression turns down the activity of a gene. 

Down’s syndrome is the most frequent genetic cause of mental retardation and affects one out of 800 babies. It is caused when there is an extra copy of chromosome 21, making three instead of two.

It causes learning difficulties and sometimes childhood heart disease and leukemia. Most people with Down’s syndrome develop Alzheimer’s disease by the age of 40.

The researchers worked with genetically engineered mice to find the gene, which is called App—short for amyloid precursor protein. Mutations are known to cause early-onset Alzheimer’s disease in otherwise healthy people.

Like people with Down’s, the mice had three abnormal copies of the App gene. When the researchers deleted the third copy of App in the mice, the animals became more normal.

“We’re now investigating ways in which we might be able to turn down App expression,” Mobley said in a statement.

“It’s not even necessary to turn it off completely. All we need to do is to reduce it by one third, from 150 percent of normal back down to 100 percent,” said Dr.Ahmad Salehi, who led the study.

The researchers stressed that deleting the third copy of App did not restore the mice to normal, so other genes must also affect the brain decline.

“First we need to figure out at a molecular level how App works in Down’s syndrome,” Mobley said. “Then we need to examine other genes that might be involved and test possible compounds in mouse and human cells. If we are able to do all that, we might begin to think of helping children and adults with Down’s syndrome to develop and age more normally.”

RELATED STORIES:
Mothers’ Exposure to Air Pollutants Linked to Chromosome Damage in Babies   Gene Therapy Reverses Symptoms of Parkinson’s Disease   More Gene Mutations Linked to Autism Risk   Computer tool helps pinpoint risky gene mutations   Scientists and physicians use genetic sequencing to identify and treat unknown disease   Brain gene makes a female develop as a male   Researchers find gene that turns carbs into fat   UN urged to ignore Bush plea for human cloning ban   Age doesn’t matter: New genes are as essential as ancient ones   Genetic differences between males and females might be evened out at the rim of the nucleus   Biotech firm wants to breed allergy-free cats   Asthma Not Determined by Genetics Alone

Comments

[ + Post Your Own ]

Now you're in the public comment zone. What follows is not Armenian Medical Network's stuff; it comes from other people and we don't vouch for it. A reminder: By using this Web site you agree to accept our Terms of Service. Click here to read the Rules of Engagement.

There are no comments for this entry yet. [ + Comment here + ]