@Russell Johnston @Wastwater
I have been thinking and searching for the genetic part of this for 20 years. Have you read Jennifer Brea’s blogs at Medium.com? She was severe, but is now in virtually total remission of symptoms following surgery for craniocervical instability and tethered spinal cord. Believe it or not, I am the one who brought ‘tethered cord ‘ to the table of discussion back in 2002-2003. Had an appt. with one of the World expert neurosurgeons after a back X-ray ( chiropractor) revealed spina bifida occulta. Did extensive reading in research literature, Long story.
Had a CINE MRI flow study with another neurosurgeon expert- very abnormal, plus small posterior fossa, steep angle Of the tentorium, short Clivus - all similar to Chiari, but no tonsillar herniation. My symptoms began after neck/ pelvis trauma, but Jennifer’s began after a viral illness.
Considering that Ehlers Danlos people have high rates of ME\ CFS/ FMS and Chiari type issues, seems likely that the genetic part may hVe to do with connective tissue differences and/ or CNS structural differences. ( biologist here - led support group 13 years).
There may be higher rates of left handed ness in our group - in the individuals or families. Interesting that the corpus callosum is very different ( larger) in left handed people. Are there other brain differences? Suspect there are differences in pelvic structure or instability due to connective tissue issues. Also, possible off midline fusion of the filum and dura at S2? Creates a torque in dural tube ? A fetal malrotation of the gut? ( This occurs early 6-8 weeks fetus - just as dural tube is forming)
There are a bunch of structural differences to look for : scoliosis, cervical, small sacral/ cervical foramina, feet differences - high arches, big bunions, hammer toes, one side of face slightly smaller, high arched palate, deviated septum, sometimes heart/ kidney things, and ??
So, maybe the genes involved are those controlling symmetry ? Connective tissue ? Or ?
Great that you are here thinking about this. Always appreciate comment.