There is a link between SWCAH and Ehlers-Danlos syndrome, for a small group of SWCAH. People with EDS very commonly have migraines, because the vessels walls are weaker, so all the triggers (hormones, MSG, etc) still trigger them, but the cerebral blood vessel walls may spasm more easily because of the deficiency of connective tissue with Ehlers Danlos syndrome.
The rate of classic carriers' genotype for SWCAH being a whole gene deletion is 20% - so as many as 20% of people with SWCAH have the whole CYP21 gene deleted. (this is publicly available on the internet thanks to Human Genome Project check out Wikipedia for more info). With that deletion, there is an adjacent gene for Tenascin X that is disrupted..... This is one cause of Ehlers Danlos syndrome.
--- this is "hot off the presses" so to speak - new research from NIH- your Tenascin X (TNX) gene itself can be normal but if it is "next to" that large CYP21 gene deletion - it does not work properly and tenascin X is still "down regulated" and the bad gene acts in a basically dominant fashion, they call it "haploinsufficiency of Tenascin X," it can cause connective tissue deficiency.
In summary, it is possible that around 20% of people with SWCAH will have manifestations of connecctive tissue deficiency. Anyway, the rate of migraines among Ehlers Danlos syndrome is probably over 90%, seems like we all have em.
