In October 2009, Loydie Jerome-Majewska and her husband Jacek Majewski made a bet: which of them would be the first to identify the gene that causes Van Den Ende–Gupta Syndrome (VDEGS)? Gene mapping of four patients with the rare genetic disorder had narrowed the search to a region of chromosome 22, but the guilty gene eluded them.
“It was actually quite a race,” recalls Jerome-Majewska, a developmental geneticist at the McGill University Health Centre in Montreal. She used knowledge of the genes in the chromosomal region that she’d acquired from her genetic experiments with mice to pick likely candidates. Her husband used a powerful new technique known as exome sequencing, which takes just a fraction of the time and cost of whole-genome sequencing to sequence only the protein-coding regions—less than 5 percent of the total human genome. By January, Jerome-Majewska confirmed her suspicion that the culprit was a gene called ...
