Charcot-Marie-Tooth Disease Study

Charcot-Marie-Tooth disease (CMT) also known as Hereditary Motor Sensory Neuropathy (HMSN) is a genetic heterogeneous disorder with a common clinical phenotype. It’s the most common inherited neuromuscular disease, with there being 200,000 cases in the EU (Pareyson and Marchesi, 2009). CMT is a group of diseases that affect the periphery nerves in the body, motor and sensory nerves are affected however in some rare cases only the motor nerves are affected; distal hereditary motor neuropathy (dHMN). The affected nerves cause characteristics such as muscle weakness and lack of sensation in the respective limbs. It can be characterised by there being no known metabolic derangement with the inherited neuropathy. It’s caused by mutations in particular
genes; so far 25 genes have been linked to CMT.
There are many types of CMT each affecting different parts of the human genome but they all have common symptoms. All types of CMT affect the distal parts of the limbs. The classic CMT patient’s symptoms are limb weakness, muscle atrophy, cramps, lowered sensation, ataxia (lack of coordination), stoopage gait and limited deep tendon reflexes. The symptoms start from the feet (figure 1) and gradually migrate up the leg (figure 2) to the lower third of the thigh. As the disease progresses up the leg, the disease will start to affect the hands and forearms. Sensory loss also follows the same path but it’s mostly focused in the hands and feet. It’s also common for patients to experience pain in their lower limbs, feet and spine, hand tremors and foot callosities (D Pareyson, V Scaioli, M Laurà. 2006). The effects of the disorder mostly start in the first 20 years of a person’s life but can occur later; it can display itself as clumsy running in childhood due to weakened ankles. The symptoms of CMT continue to get worse until most patients will need to use walking aids and in extreme cases a wheelchair.