People with CMT tend to slowly lose normal use of their limbs as the peripheral nerves degenerate. The muscles in the extremities often become weakened because of the loss of stimulation by the affected nerves. Sensory nerve function may degenerate as well. Unlike muscular dystrophy in which the defect is in the muscles, CMT is a disorder in which the defect is in the nerves that control the muscles. As the disease advances, structural foot deformities such as the appearance of a high arched foot and hammer toes can occur.
Progressive muscle wasting leads to problems with walking, running, and balance.
To avoid tripping, patients with foot problems often raise their knees unusually high, resulting in a distinctive gait. Hand function also becomes affected because of progressive muscle atrophy, making fine movements, such as writing, difficult. Loss of nerve function in the extremities can also lead to impairment of the sense of touch as well as the ability to distinguish hot and cold. Aside from pain that can make running, walking or even standing impossible, the disease can also be enough of a distraction that it routinely interferes with sleep, leaving sufferers little respite. Although symptoms usually grow worse over time, their level of severity can vary dramatically.