The somatic super syndrome

Connective tissue is the material that holds you together. It is in your skin, your ligaments and tendons, the walls of your blood vessels, your gut, and the covering around every organ. Collagen is its main structural protein.

That list is why a difference in connective tissue does not stay in your joints. If the same material is in the blood vessel walls and the gut wall, a difference in it can show up in blood pressure and digestion as well as in bendy fingers.⁴⁵

Joints that move further than the usual range. On its own that is a description, not a condition, and plenty of people have it without any trouble at all.

What does differ, measurably, is position sense. A 2025 study found hypermobile people had poorer joint position sense at the elbow and knee, while grip strength and functional stability were no different from anyone else.⁴²

Same thing, different words. Double jointed is the playground term and it is inaccurate, because nobody has two sets of joints. The joints simply move further.

The useful question is not whether you are bendy but whether it causes you problems, and that is a separate question with a separate answer below.

When it comes with symptoms: pain, joints that give way or dislocate, fatigue, and the other body systems joining in.

A survey of people with hypermobility in a localised or historical pattern, rather than the classic widespread one, found they reported significantly more symptoms and co-occurring conditions than expected.³³ Being bendy in only a few places does not mean being mildly affected.

Hypermobile Ehlers-Danlos syndrome, hEDS, is a heritable connective tissue condition diagnosed on clinical criteria rather than a blood test. It is described as likely the most common heritable connective tissue disorder, and as underdiagnosed, partly because it lacks the obvious skin features of the other types.¹⁴

There is still no gene test for it. When genetic testing was used in people who met the clinical criteria, 26.4 per cent turned out to have an additional or alternative diagnosis, which tells you both that the criteria catch a mixed group and that testing has a role in sorting it out.³²

Hypermobility spectrum disorder, HSD, is symptomatic hypermobility that does not meet the full hEDS criteria. It is not a lesser problem, it is a different label.

A global survey put numbers on that. People with hEDS reported an average of 24 co-occurring conditions and a diagnostic delay of 22.1 years. For HSD it was 17 conditions and 17.5 years.³⁴ Both groups wait most of their adult lives.

The Beighton score is the nine point check for how far a set of joints move. It is quick, it is widely used, and it has real limits that are worth knowing before you take a score to heart.

A review of the evidence found agreement between examiners is moderate at best, and rated the reliability evidence as limited to conflicting. The familiar cut-off of four or more has no evidence-based derivation behind it. Two thirds of the joints it tests are in the upper limb, so it does not capture how systemic your hypermobility is, and a low score cannot rule generalised hypermobility out.³⁰

A 2026 systematic review with meta-analysis set out to fix exactly that by deriving cut-offs from data rather than convention.³¹

So: a useful starting point, not a verdict.

Because flexibility and stability are not the same thing. A joint that travels further has further to travel before anything stops it, and the muscles around it work harder to do the job the ligaments are doing less of.

Hypermobility is well represented in chronic pain populations.¹⁵ There is also emerging work implicating the position sensors in muscle themselves in the development of widespread soreness, rather than pain nerves alone.⁴¹ That is early laboratory science, not an explanation of your pain.

Proprioception is your sense of where your body is without looking at it, and it is measurably less accurate in hypermobile people at the elbow and knee.⁴²

If the information about where your arm is arrives slightly blurred, you find door frames with it. That is a sensory difference, not clumsiness in the character sense.

Standing up is a challenge your body has to answer. Blood drops towards your legs, and your nervous system has to tighten the blood vessels and adjust your heart rate to keep blood going to your brain. If the vessel tightening is weaker than it should be, the heart rate has to do more of the work, so it climbs.

A sustained rise of more than 30 beats per minute on standing, with symptoms, is the pattern that defines postural tachycardia syndrome.³⁷

Postural tachycardia syndrome, PoTS, is that sustained rise in heart rate on standing together with symptoms such as dizziness, breathlessness, fatigue and brain fog, in the absence of a drop in blood pressure that would explain it.³⁷

It is a recognised condition with a substantial disability burden, and it needs proper testing and specialist input rather than reassurance.³⁷

Dysautonomia is the umbrella term for the automatic nervous system not regulating properly. PoTS is one form of it. That system handles heart rate, blood pressure, temperature, digestion, sweating and bladder, which is why dysautonomia rarely shows up as one tidy symptom.⁴⁸

It occurs alongside a long list of other conditions rather than only on its own.⁴⁸

Yes, and this is where a lot of women lose years.

A racing heart, breathlessness, shakiness and a sense of dread are what an anxiety attack feels like and also what an autonomic response feels like, because they involve the same machinery. The difference is what sets it off: standing up, heat, a hot shower, a large meal.

There is published work on the connective tissue and autonomic route into psychiatric symptoms specifically, arguing that the body's signalling is part of the picture rather than a misreading of it.⁴⁵

Anxiety can be real and present at the same time. The point is that it should not be the only thing anyone looks at.

Mast cells are immune cells that sit in the tissues that meet the outside world: skin, airway, gut. When triggered they release histamine and other chemical messengers, which is what produces flushing, itching, swelling and the rest of an allergic-type response.

They also talk to the brain. There is a research literature on mast cells and behaviour, including their role in conditions that are usually thought of as neurological rather than immune.²⁴

Mast cell activation syndrome, MCAS, is mast cells releasing their contents when they should not, producing symptoms across several body systems at once without a classical allergy to explain it.

A case series described the neuropsychiatric side of it specifically, which is the part most often missed when someone presents with brain fog and anxiety rather than hives.⁴⁷

MCAS is a contested area of medicine with criteria that are still argued over. Uma will not pretend that argument is finished.

Because oestrogen acts on mast cells. That mechanism is established in cell and animal work: estradiol activates mast cells through a rapid route involving calcium, and mast cells from animals lacking the relevant oestrogen receptor do not respond to it.⁴⁹

The human side is observational. A substantial proportion of women with asthma report symptoms worsening around menstruation.⁴⁹

So the mechanism is laboratory evidence and the monthly pattern is an observed association. Uma keeps those two apart.

Three reasons that stack. The gut wall is connective tissue. The gut is run by the automatic nervous system. And mast cells live in the gut lining.

There is a clinical review written specifically for gastroenterologists on hEDS and the gut, which is a fair indication that the association is taken seriously in that specialty rather than being an internet theory.³⁵

A scoping review of brain fog in chronic pain describes it as a fluctuating state affecting memory, attention and daily functioning, and says plainly that it remains poorly defined and poorly understood.⁴³

In PoTS there is a mechanism worth knowing: if blood flow to the brain is not maintained properly when you are upright, thinking is harder when you are upright.³⁸ That is a plausible route, not a settled cause.

Fog is a real, describable phenomenon that has not been properly studied. Those are two different statements and both are true.

The overlap is documented. A survey of 733 people with hEDS or HSD found high overlap with fibromyalgia and with 40 self-reported symptoms and co-occurring conditions.⁴⁴ A study of hEDS using formal autonomic testing found cerebrovascular, autonomic and small fibre findings in the same group.³⁸

What is not established is that these three form a single named syndrome with one cause. The associations are real and repeatedly observed. The underlying mechanism is still being worked out, and the diagnostic boundaries are still argued over.

Uma describes them as often reported together rather than as a triad, because that is what the evidence supports.

The association is reported in both directions. A retrospective study of children with hypermobility spectrum disorders or hEDS found ADHD diagnosed at more than three times the general population rate.³⁹ A review of autism and the Ehlers-Danlos syndromes sets out shared genetic and nervous system features and raised rates of one alongside the other.⁴⁰

A study using formal autonomic testing in autistic people found 71 per cent had an autonomic condition, most commonly PoTS, and of those, 80 per cent also had hEDS.³⁶ That was a clinic sample rather than the general autistic population, which matters for how far the number travels.

There is a published model for exactly this. It links emotional dysregulation in neurodivergent people to the effect hypermobility has on proprioception, the sense of where your body is.⁴⁶ In the data behind it, the link between imprecise proprioception and emotional dysregulation appeared only in people who were also hypermobile.⁴⁶

It is a proposed model built on a cross-sectional study, so treat it as the best current explanation rather than a proven chain.

Because the standard panel is not testing for any of this.

hEDS has no blood test. It is diagnosed on clinical criteria, and genetic testing is used to rule other things out rather than to confirm it.^14,32 PoTS is diagnosed by measuring heart rate and blood pressure on standing, which a routine appointment does not do.³⁷ The autonomic findings in hEDS were picked up using formal autonomic testing, not a blood count.³⁸

A clear result on a test that was never looking for your condition is not evidence that nothing is wrong. The average diagnostic delay of 22.1 years in hEDS is built out of exactly those appointments.³⁴