so every time you have a cag, you get a glutamine. and in most of us, those glutamines are functioning in the protein. but what happens in huntington's is that gets expanded, and when the number of glutamines gets expanded in the protein, that confers a toxic property to it. and that causes cell death, and aggregation. so what happens with huntington's disease is that if you inherit more than 39 of those cags, you will get huntington's, and alan got it at 59. >> rose: so if you're more than 39 you are at high risk and you will definitely get it. >> you will definitely get it if you live long enough. if you inherit fewer than 35-- just think, there's only four difference there-- if you inherit less than 35, you will never get it. >> rose: no risk. >> what's wonderful about the insight it turns out this is not unique to huntington's. >> that's right. >> cag repeats in other diseases as well. >> exactly. so it turns out after this was discovered there are maybe 10 diseases that have this cag expansion. they all affect it the nervous syst

cag out of fauquier and loudoun. about to move into fairfax. there's the heavy stuff, though. see it up toward just south of bwi crossing route 1. silver spring, heavier shower there. if you're approaching the beltway, you'll see that heavier shower also from 66 about to move into fairfax. let's go inside and check in with monika, talking about route 66. how is it looking? >>> that is not too bad this morning. on the inbound side of i-66 just a little heavy between manassas and centreville but other than that, 66 has been good. no problems on the bw parkway or route 50 through cheverly trying to get into the northeast corridor. in my last report i did tell you about some issues over on the bay bridge. inspectors have closed down the westbound side for the morning rush hour due to some emergency inspections that they need to do. let's take a look live there. it is causing delays because what they're doing is diverting this traffic on to the eastbound span which is now going to carry two-way traffic for the morning rush hour. so this is the westbound side of route 50 trying to g