Early symptoms,from childhood, for me were being unable to run, skate, or play sports. Also high arches and weak ankles. I have always been very clumsy and accident prone. My sister wore braces for drop foot fom early childhood. I did not develop numbness until my early 30's, but it has progressed from my toes to above my knees, like your grandmother. I am now 50. I have had progressively more pain and weakness in my legs, as well as my hands and arms, as the years have gone by, and the symptoms have really accelerated in the past three years. I walk with a cane, and am losing the ability to go up stairs.
As Kitt said, everyone's symptoms, onset, and progress are different. I have CMT type 2, axonal degneration. My EMG/NCS is abnormal and shows large fiber neuropathy, my skin punch biopsy shows an advanced small fiber neuropathy. I have very limited ability to move my toes, and there is visible wasting of the muscles in my feet and lower legs.