The finding is documented in the March 24 issue of Nature Genetics, a prestigious peer-reviewed British journal.
SMS is a chromosome microdeletion syndrome that is characterized by a very distinct series of physical, developmental and behavioral features, including varying levels of mental retardation, cranio-facial abnormalities, sleep disturbances and self-injurious behaviors.
Because the disease is manifested in so many ways and is associated with a chromosomal deletion that includes many genes, it was always assumed that more than one gene contributed to the disorder, said researcher Sarah Elsea.
"This disorder was assumed to be a contiguous gene syndrome," said Elsea, an assistant professor in the departments of Pediatrics and Human Development and Zoology. "However, our data show that primarily one gene contributes to the phenotype."
What Elsea and colleagues found was mutation on a gene identified as retionic acid induced 1 (RAI1) that prevents the production of normal protein from that gene.
"The result of this mutation is that the protein can't be formed properly," she said. "Individuals with SMS have one normal functioning RAI1 protein from one chromosome, but from the other chromosome they are not getting this protein function at all."
Because SMS is a sporadic genetic disorder, prevention is pretty much out of the question, Elsea said. However, early diagnosis of the disorder can lead to improved outcomes.
"I think that in the future, if we understand what this gene, this protein, does and how it interacts with other proteins in the cell, we might be able to develop some kind of drug therapy that might help deal with the behaviors a li
Contact: Tom Oswald
Michigan State University