Like Trudie, I am curious what treatment you are receiving. Also, what tests have been run? I would think seronegative RA could not be ruled out especially in light of your family history. How many rheumys have you seen? Have you contacted a support group in your area to get a recommendation on a doctor to see?
What kind of treatment are you on? Great success at stopping the progression of disease has been found with anti-malarials and immune suppressant drugs.