I am sorry that your daughter is experiencing problems. Arthritis in childhood is a much misunderstood disease. The signs, symptoms and problems associated with it are different then adult disease. I am glad to hear that she has been referred to a Rheumatologist, but it would be better to see a Pediatric Rheumatologist if that is at all possible. (They are few and far between.) If she does have Spondylitis or RA, (the chances of her having both are remote) her doctor should be able to help her get her symptoms under control so that she can lead a completely normal life. Early diagnosis and early aggressive treatment have been shown to be most effective in dealing with juvenile Arthritis/Spondylitis.
Doc has referred her to the rheumy I see but thinks she has early onset adult RA as opposed to juvenile RA.
Most children with Juvenile Arthritis (in any form) do not have a positive Rheumatoid Factor. The positive Rheumatoid Factor result in a child can be an indicator of more adult type RA.
I have so many questions but I guess the main ones are.
What are the differences between AS and RA?
Does the HLA-B27 gene affect RA or only AS?
What syptoms should I look out for/what to expect?
Juvenile Ankylosing Spondylitis does exist, but is extremely rare. This diagnosis would indicate that the patient had enough evidence on imaging to diagnose adult AS (Sacroiliitis bilaterally grade2+ or unilaterally grade 3+). Most kids with Spondylitis have Juvenile Spondyloarthropathy (JSpA - think Undifferentiated Spondy) or Enthesitis Related Arthritis. JSpA can affect the back, and really any joint, but predominantly effects joints in the feet, ankles, knees and hips. Enthesitis Related Arthritis is more enthesitis related and seems to be applied more frequently to kids who are HLA-B27 negative.
HLA-B27 has a relationship to AS but not to RA. It is possible to have RA, be HLA-B27+ and not have AS. As you know HLA-B27 is a perfectly normal gene in 8% of the population. Most never develop AS. Even with HLA-B27+ and the strong family history, her chance of eventual AS is increased to 20%. However, add in the current joint pains and other symptoms ..... Best to let a qualified Rheumatologist make that assessment.
While waiting to see the Rheumatologist, I would take note of any joint swelling, heat, or pain/stiffness she experiences. Other symptoms like fatigue, lethargy, fever, etc should also be communicated to the Rheumatologist. Any indication of eye involvement should be dealt with immediately - JRA can effect the eyes too.
By the way, in the US anyway, JRA is now more commonly referred to by physicians as JIA - Juvenile Idiopathic Arthritis. I don't know if it is the same in other countries. It is generally considered Juvenile (JRA, JIA, JAS, etc) if the problem begins before the age of 16 - regardless of the form or severity of the disease.
I hope she gets in to see the Rheumatologist soon.