In the September, 2004, issue of Nature Genetics -- to be published online August 22 -- the researchers show that in humans, loss of one copy of each of two adjacent genes, known as ZIC1 and ZIC4, causes Dandy-Walker. The researchers then used this finding to create a mouse model to allow them to study the developmental basis of the disorder.
"Dandy-Walker malformation is an important clinical problem as well as a scientific mystery," said study co-author William Dobyns, M.D., professor of human genetics, neurology and pediatrics at the University of Chicago and an author of the study. "We see about 20 cases per year, but until recently, there was not even an understanding that Dandy-Walker had a genetic basis."
"Knowing more about the genes also should improve our ability to make a prenatal diagnosis," he added, "which has always relied upon ultrasound. Finding the genes will help us inform parents about the risks of having another affected child."
"This discovery provides one of the first real avenues for understanding human birth defects that affect the cerebellum," said study author Kathleen Millen, Ph.D., assistant professor of human genetics at the University of Chicago. "Until now, we have had no understanding of what goes wrong during development to cause this malformation. We now know some of the genes involved and have a mouse model to study to figure this out."
This work may also have broader implications. Understanding what goes wrong in Dandy-Walker malformation coul
Contact: John Easton
University of Chicago Medical Center