Map of Chromosome 21 Reveals Secrets of Down Syndrome

In a recent study, researchers used the gene map of chromosome 21 to study how the extra genetic material present in trisomy 21 (Down syndrome) causes mental retardation and physical abnormalities. The study appeared in the December 5, 2002, issue of Nature.

Investigators studied mouse genes that correlated with the human genes on chromosome 21. Their method was a combination of large-scale mRNA hybridization and computed mining of expressed sequence tags on samples from early developing mice and from the brains of two-day-old mice. They have discovered where in the brain the switched-on genes are found, which may lead to the identification of the contributing genes.

"Our study provides a road map with clear signposts to the culprits of Down syndrome,” explained Dr. Ariel Ruiz i Altaba, associate professor of cell biology at New York University School of Medicine (NY, USA), one of the lead authors of the study. "There are now clearly defined candidate genes in the brain, heart and elsewhere that we can look at. The next step is to understand how these genes function normally. Once we know which ones cause defects in the brain when their expression is altered, we will be in a position to see if rational therapies for Down syndrome are possible.”




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New York Univ. School of Medicine