Have you found patients with more than one mutation on the RAS pathway?

Yes. But sometimes we only look for one gene like PTPN11; we weren’t systematically looking at all but now we run a panel of maybe 10 or 12 genes and we occasionally find one that’s got more than one gene fault. It is possible for example to have a child with both the Noonan gene and another genetic condition causing short stature. It’s going to happen by chance occasionally but probably relatively rarely but with increasingly accurate testing, there will be more identified. It does seem to be a chance event rather than any biological principle underlying it.