DOCUMENT

10 | InTouch FEBRUARY 2022 Also known as hereditary motor and sensory neuropathy, Charcot-Marie-Tooth disease (CMT) is a condition that affects the nerves that send information from your brain and spinal cord to and from the rest of your body. Charcot-Marie-Tooth disease (CMT) also known as hereditary motor and sensory neuropathy (HMSN), comprises a family of genetic conditions that mainly affect the motor and sensory nerves, which run from the spinal cord down the arms and legs. It is caused by alterations in genes that produce proteins involved in the structure and function of either the peripheral nerve cell (axon), or the myelin sheath that wraps around the axon to insulate it and in normal circumstances allows the signals to travel faster and better. Key points 1. CMT is inherited through one or both of your parents’ genes. 2. Symptoms of CMT usually start between the ages of 5–15 and get worse over time. 3. It affects feet and legs first, then later hands and arms. 4. Unfortunately, there is no cure for CMT. Treatment aims to reduce symptoms and help with daily functioning. 5. Living with CMT can be difficult and challenging both physically and mentally. However, there are support groups available to help you cope with the condition. What are the causes of CMT? The nervous system in your body consists of the central nervous system Charcot-Marie-Tooth disease (CMT) YOUR CONDITION IN REVIEW (CNS) and the peripheral nervous system (PNS). The central nervous system is made up of your brain and spinal cord. The peripheral nervous system is made up of nerves that carry messages from your brain and spinal cord to other parts of your body. The peripheral nerves have motor and sensory nerves. Motor nerves carry messages from your brain and spinal cord to your muscles, telling them to contract. Sensory nerves carry stimuli such as touch and pain in the form of signals to your brain and spinal cord. A peripheral nerve’s structure can be seen in the image above. The axon is similar to the wiring of an electric cable that transmits messages between our brain and spinal cord and the rest of your body. The myelin sheath wraps around the axon and acts as a protection layer, similar to the insulation of a cable, to make sure electrical messages are not broken while they are being sent. There are many types of CMT based on the specific gene abnormalities involved in the structure and function of axons or myelin sheaths. The principal types include CMT1, CMT2, CMT3, and CMT4. Onset of CMT3 and 4 will usually occur before 3 years of age. The severity of symptoms will vary greatly from person to person even within the same family. What are the symptoms of CMT? The symptoms of CMT are different for each person and depend on the types of CMT. As it is a progressive condition (symptoms get worse over time), it is sometimes difficult to spot symptoms and diagnose a child with CMT. Diagram showing peripheral nerve structure.