STXBP1 Description--The Bubble Bath

This is the first plain English description of Cailyn's genetic anomaly that I've ever seen.


STXBP1 and the bubble bath.

In order to understand the function of STXBP1, just imagine a bubble bath (on Sunday evenings, our little daughter usually has a bath, therefore, this example was obvious to me). Imagine two medium-sized bubbles floating on the water. What does it take to turn these two bubbles into one big bubble? Yes, it is quite difficult. The more you try to push them together, the more you risk generating many small bubbles rather than a single big one. For soap bubbles, this task is a bit easier, but also here you will end up with a burst bubble rather than a single big bubble in many cases. In terms of (bio)physics, the joining of bubbles is a matter of overcoming the repulsive forces when joining two lipid bilayers, i.e. it’s not natural for bubbles to join, you have to give them a push. To cut a long story short, why is this relevant for the human brain? Our synapses have the same problem thousands of times each millisecond. In order to enable synaptic transmission, we need to fuse synaptic vesicles. Each of these vesicles needs a little push to fuse with the presynaptic membrane. And STXBP1 is one of proteins providing this push.

Today's Biology Lesson

So we were contacted by Cailyn's geneticist a few weeks ago that they've finally come up with answers.

We've been testing Cailyn for various genetic and chromosomal issues for almost three years now. First at Johns Hopkins and then at the Kennedy Krieger Institute, also in Baltimore.

They've tested blood, blood sugars, proteins, spinal fluid, MRIs etc. So it ends up Cailyn has an anomaly in a neurotransmitter protein called STXBP1. It has only been discovered in the past year so it's super new science. Ends up Cailyn is the first case of STXBP1 at Kennedy Krieger.

It will not change anything in how we treat her. Since it's gene stuff it's not "fixable". The two biggest things with this protein are intractable seizures and developmental delays. Nothing new on that end, these were both things we already knew. The one new thing we found out is that this is NOT inherited so if we have other children there is only a 1 to 6% chance they would have the same anomaly, so 94% chance or greater that this would NOT occur again.

So no new steps for now. We are still supposed to stick with her neurologist for seizure control and all her therapies to improve her strength and skills.