Peroneal muscular atrophy
An unusual, inherited disorder characterised by muscle wasting in the calves and feet and then in the hands and forearms. The condition, which is also known as Charcot-marie-tooth disease, is caused by degeneration of certain peripheral nerves. It often appears in adolescence or late childhood.
Muscle wasting ceases half way up the arms and legs, making them look like inverted bottles; sensation may be lost. There is not a treatment for the disorder, but it is very unusual for the afflicted to become completely incapacitated because the disease often progresses at a very slow rate. Life expectancy is that of a normal person.