Mechanisms involved
This condition is explained through the mechanisms below. Each one is taught as ordinary physiology first.
Primary
Secondary / contributing
Immune cells involvedWho is actually in the tissue
Tentative, and included because the question is asked constantly.
Selected cell
Macrophage
Clears debris and old blood. When clearance is incomplete it switches to a repair-and-inflame phenotype that feeds fibrosis and new nerve growth.
Microglial differences are reported in autism research, but this is descriptive work — not a cause, and not a treatment target.
Schematic drawings, not micrographs. Immune findings here describe mechanism and association; none of them are diagnostic tests.
What it is
Chiefly autism and ADHD here: developmental differences in how sensory input is filtered, attention and effort are regulated, and body state is read. Not illnesses, but highly relevant to chronic-illness care because they change what an appointment, a symptom log and a treatment plan need to look like.
How the mechanisms produce this
- Reduced sensory filtering means clinical environments cost energy before the consultation begins.
- Interoceptive differences make pacing hard to learn from feel alone, which is why external data helps.
- Hypermobility is found more often in autistic and ADHD populations than in matched controls, and the connective-tissue and proprioception link is the most plausible route.
- Masking is metabolically expensive and shows up as fatigue and post-social crash rather than as a social complaint.
What tends to help
- Environmental accommodations treated as clinical, not personal, requests.
- Written summaries before and after appointments; processing time is not indecision.
- External tracking for pacing where interoception is unreliable.
- Screen for orthostatic intolerance and hypermobility rather than assuming symptoms are anxiety.
Where the evidence is thin
The hypermobility association is consistently observed but the mechanism linking them is still hypothesis, not established fact.