Of course, there are occasional cases of JRA occurring in families although this is extremely rare. As a matter of fact, one part of our ongoing research is to have a National Registry of all the brothers and sisters with JRA so that we can conduct a more organized approach to finding out why their families were affected in that way. A separate question is about the arthritis and how it relates to other family members who already have arthritic conditions. Arthritis is one of the most common chronic conditions. The most common form of arthritis is osteoarthritis.
Most people have family members, particularly in the older generations, who have arthritis.
In all likelihood, osteoarthritis does not relate to the JRA that your child has developed. There are certain genes that are more common in different types of diseases. However, the genetic component of arthritis has not been fully worked out at this time. This is probably one of the most common questions to be asked. Unfortunately, we don't know how to predict how the disease is going to progress or have a way to offer a firm prognosis.