How to increase lower leg (ankle & lower 1/3 of calf) mass due to muscle atrophy (CMT)?

I suffer from Charcoot Murray Tooth disease and as a result have incredibly thin calves and ankles. I am extremely embarrassed about them as I am 6'6" and 106kg, so they stand out quite a bit. I am 35 years old and have not worn shorts in public since I was 13. I have had several corrective surgeries to the bones and tendons in my right foot to help walk, but I am resigned to the fact that I will end up in a wheelchair at some point. I'm basically looking for a way to make my legs look normal.