they found a mutation in a particular gene that makes a protein called leforrin.is it possible what we're talking about with kylie is truly something that's never been described before? >> it's very possible. >> brand new? >> brand new mutation and maybe identifying a gene that is not known previously to cause a human disease. >> back home in reno, nevada, gina and steven are trying to focus on enjoying the time they have as a family. although kylie is deteriorating, she's happy. >> maybe someday we'll get that phone call, hey, we think we might know what it is. >> in bethesda, maryland, the doctors at the undiagnosed disease program are digging deeper. they're doing a dna analysis of kylie's parents and sisters. they know it is now a race. >> every new case that comes to us brings with it a human story. i think the important thing is for us as professionals to look at the successes that we have and to try to not dwell on the -- on the failures that we have, because we fail so often. >> but not always. luckily for sally massagee, the experts at the udp solved her