Spontaneous fractures and still undiagnosed

Back pains started when i was 11, it developed to arthritis. At the age of 15 I had my first spontaneous fracture. I have normal calcium levels, very low phosphate levels  ( Hypophosphatemia ) and high alkaline phosphate. The only medicine I take is Phosphate Sandoz but no matter how much i eat phosphate high food or take the medicine, my body doesn't recognize it, and no doctor understands where does the phosphate go. Now I am 19 and have both hip fixators , and have had around 10 spontaneous fractures. They have done so much research about my symptoms but nothing fits with some particular disease ( they have considered Oncogenic hypophosphatemic osteomalacia, but the tumor is nowhere to be found ). We have consulted around the world, but noone knows whats the reason behind this. I am desperate for help , I want to be healthy again!

[coxyart]

You don't mention in your post if you have had blood tests for FGF 23 and 1,25 Dihydroxyvitamin d levels,Oncogenic Osteomalacia can be difficult to diagnose because the mostly benign tumours are very small but they can sometimes be found if memory serves with an Octreotide scan.This condition can also be relieved in some cases with high doses of Calciferol (a type of vitamin d) but long term doses need to be monitored closely.To complicate matters further there are other conditions which essentially mimic this disease they are ADHD, and XLH, both genetic conditions which generally present in early childhood although in some cases ADHD can present in adulthood.  

[coxyart]

Sorry that should be ADHR (AUTOSOMAL DOMINANT HYPOPHOSPHATEMIC RICKETS), ADHD is something completely different!