I'm trying really really hard not to get into the specifics of hEDS because that isn't what this thread is about and there are multiple threads over multiple years that do get into the problems with it as a diagnostic entity.
I guess it may be what this thread is about, if not explicitly.
I have been trying to get my head around the problem with the diagnosis and I think I have worked out what it really is.
EDS was recognised decades ago as a connective tissue abnormality with a dominant inheritance pattern, giving strong family pedigrees. There are several types and it was established that there are several genes that can be defective. Most defective mutations are Mendelian dominant but a few are X-linked recessive. X-linked recessive mutations behave as if they were dominant, but only in males.
In simple terms this means that EDS runs strongly in families with on average half of the children of an affected person, or half of the sons of a carrier woman, being affected. The other children are normal and there are no in-betweens.
The broadening of the concept of EDS from that of a single disease to a cluster of rare dominant pattern inherited diseases started even before we knew that genes were DNA I suspect. By the 1970s there were several types of EDS defined. EDA III was defined as only producing joint hypermobility (pretty much).
Some time around the 1970s or 1980s people stared saying that joint hypermobility and EDS III are the same thing, because they describe the same presentation - joint hypermobility. But
the mistake here is to forget the Mendelian dominant inheritance indicating a single gene mutation. This is not just having a family history, which you will get with polygenic hypermobility - which is like being tall, just the end of a spectrum. Mendelian pedigrees are very specific and are important because they indicate a
single gene disorder.
People at the mobile end of the hypermobility spectrum may get just as much trouble from lax joints as people with EDS, and maybe more. However, I suspect very few have a single gene disorder. The problem for the hEDS diagnosis then is that it has no boundaries - just as being tall has no boundaries. That means that there are no 'experts' who can diagnose hEDS better than someone else. It is a matter of arbitrary choice. Criteria can be invented but they have no particular merit.
As indicated by the letter above, the 'experts' in the UK have been using terms like hEDS in a way that looks to be a potential cause of harm. In the past I was right in the middle of that and left the field because I was not happy that patients were being advised helpfully.