"Most efforts are on the very common disorders," said Wahlestedt, of Scripps Florida. "It's always a challenge to find resources to work on [rare conditions]."

It took Wahlestedt and his team only a year to identify a second gene involved in fragile x. Wahlstedt is awaiting a patent for the newfound FMR4 gene, on the X chromosome most known for determining a baby's sex.

"We definitely found something new and that's kind of cool," he said. "We have to prove it's important for the disease. That's a long road."