Mix-matched leg length discrepancy

I have a 3yrs 5mo daughter with Turner Syndrome, ADHD, PDD NOS, SPD, Anxiety Disorder, ADHD combined who last year we noticed a leg discrepancy. We took her in and was told we caught this very early was X-rayed and sent to Scottish Rite, Dallas TX (Nov 08). There we were told this is not TS related but had no explanation for the odd discrepancy as her left femur  is longer than her right but her left tibia is shorter than her right, therefore making her right leg slightly longer. We were sent home to wait a year or until things changed, it is now April and it has now become noticeable for her Endo to spot and we're going back in for X-rays. My question is what could have caused this as our Endo, Ortho and Geneticist have no clue? And what type of treatment for her mix-matched leg length discrepancy, due to her taking growth hormones for TS?
And one major concern is her anxiety and sensory issues with all this.

Thanks
Janine