My 11 year old daughter have had prolonged fever last September. Temperature up to 40C. doctors were unable to root out the cause for us. She has high blood platelet count around 700 x10^9/L. She went under bone marrow biopsy with negative result stating that her increase in platelet is only a reactive activity of bone marrow. Our hematogist have advised to take JAK2 mutation . Right now she has dissented stomach and she cannot defecate daily, there are times she would complain about her heartbeat being too strong, she looks very tired sometimes she would sleep for more than 12 hours a day especially on weekend.Her appetite is ok, she eats normally.right now i m monitoring she ll be in fruit & vegetarian diet to clean her digestive system to regularize her bowel movement .Physically she lost weight from the time it all started. Probably around 2-4kilo lost. What could possibly cause it. JAK2 mutation seems to be looking into myloproliferative disorder which i thought would have been figured out during her bone marrow biopsy. Would appreciate if you can send some suggestions.