A team of researchers has discovered a genetic syndrome that causes childhood obesity, intellectual disability and seizures. The syndrome comes from an “unbalanced” chromosomal translocation: affected individuals have additional copies of genes from one chromosome and fewer copies of genes from another.
The results were published this week in Proceedings of the National Academy of Sciences, Early Edition.
Katie Rudd, PhD, assistant professor of human genetics at Emory University School of Medicine, is senior author of the paper. Research specialist Ian Goldlust, now a graduate student in the NIH-Oxford-Cambridge Scholars Program, is the first author. Co-authors include investigators from around the USA and Australia.
Rudd’s team was able to connect the contribution of one gene, GNB3, among many involved in the translocation, to the obesity aspect of the syndrome. Her lab created a mouse model with an extra copy of the GNB3 gene and found that the mice are obese. The mice are on average 6 percent (males) or 10 percent (females) heavier.
Rudd says her work was greatly assisted by collaboration with the Unique Rare Chromosome Disorder Support Group, a UK-based charity. Within Unique, a few parents had together found that their children had translocations involving the same chromosomes and similar symptoms. They contacted Rudd and helped her find additional affected families. Her study includes seven unrelated patients.
“It really was a group effort, and Unique was the linchpin,” she says. “Managing to find seven families with exactly the same rare translocation would have been extremely difficult otherwise.”