I typed this out hours ago - but for some reason it did not post. Trying again!! Was on my smartphone and trying to type a proper reply was just too pesky!
OK firstly don't worry. Hypermobilty does not have to be a horrendous thing. I have lived with it my whole life. My family on my Dad's side have a genetic tendancy to Ehlers-Danlos type 2 - 3. That is the most common type and many people suffer without even realising that that have a "condition". My DD who is 8 has it too and is super stretchy, and super agile. She honestly views the whole thing as some kind of super power!! For me the aches and pains did not set in until puberty and I suspect she will be the same.
Have a look on the support site for Ehlers-Danlos support UK www.ehlers-danlos.org/ they have lots of great info. Also www.hypermobility.org has fab info. Read up on it - but do not be freaked out when you read the descriptions of the types and look into the higher numbered types where people are claw handed or in wheelchairs, that is not the hypermobile form of EDS. This would be generally diagnosed very early AND is VERY rare. Most people have types 2 - 3. Which are very managable.
The diagnosis for this is via Brighton Scale tests, many of which you can perform yourself. If your DD has it, it is likely either you or DH do. Note that the types do not mutate over generations - so if type 2 runs in your family she will have type 2 and so on.
The best thing you can do is do good healthy excercise which keeps her joints and muscles strong. Suddenly stopping excercise fearing it will do her harm will result in problems / pain over time. So good healthy excercise. Nothing special just good old child like fun. Yoga helps - there are loads of good kids yoga classses - as it helps with strengthening. EDS hypermobility is a collogen disorder.
The best specialist in the UK to see for this is Professor Rodney Grahame, Emeritus Professor of Rheumatology, University College Hospital, LONDON. He also has a child's clinic at Great Ormond Street. You can ask your GP to be referred www.uclh.nhs.uk/OurServices/Consultants/Pages/ProfRodneyGrahame.aspx this is his info. He is a lovely man and very good with kids. He made my DD feel very comfortable and sorted any concern we had. Your DD will also be sent for an echo cardiogram so they can see if she has Mitral Valve Prolapse which can crop up in EDS sufferers. MVP can be serious but in many cases it is minimal. My DD has it, (but it is not serious enough for them to be concerned.) again nothing to worry about but it is good to know.
Is she particularly long in the body, with long arms? Does she have a long face? Do you or hubby? Is her wingspan wider than her height? Does she generally "W" sit? do you or hubby? Is she fidgety, does she get uncomfortable easily? Is her skin Stretchy? Do you or DH look great for your age?? These are all indicators.
To put your mind at rest. Prof G sees many many incredibly able bodies folks who are EDS suffers. Many ballerinas, gymnasts and acrobats are EDS. Their body is stretchy because of it and has allowed them to persue those careers. They just need good excercise to manage thier collgen strength. It affects me by making me look younger than I am (our skin is normally very good and stretchy - my gran looked 65 at 90!!) It makes me very supple. On the down side from age 14 onwards at the change of seasons I had pain in my joints, not major but it was there. If I lean on one arm for example for too long it will hurt longer. Sometimes it gets me down, other times I seldom think about it. Everyone suffers differently. My hubby also has marfan in his family which is a related condition, but fortunately thus far it has not caused anything too akward in DD>
Remember if your DD is hypermobile she will be able to do lots of crazy stuff like the splits etc. She will still feel the pain (as we would) of dropping into the splits without warming up) and she may well be ablet o do it. But her muscles will hurt afterwards and she may damage them sprain them trying to do stuff without warming up. So encourage her to do warm up excercises if she does intend of being daring. We have found rock climbing (I know your DD is too young yet) is a fantastic way of building and keeping up excellent muscle strength and our whole family go often. DD is like a lizard and enjoys it so much she has no idea why we do it.
Have to go now off to a party - but if you have any questions fire away. My family has lived with it and still do.
Good luck xx