The symptoms of Charcot-Marie-Tooth (CMT) disease can vary considerably between individuals. The onset, progression and severity of symptoms are largely unpredictable and depend on the type of disease and the specific individual case.
Most individuals with CMT notice the primary symptoms of the disease between the ages of 5 and 15. However, they may not become evident until adulthood in some cases. Some types, such as CMT3 is associated with an early onset of symptoms, usually before the age of 2 years.
The early symptoms of CMT can be difficult to recognize in young children with the disease, as they can be subtle and usually progress in severity with time. Early signs may include:
- Abnormally clumsy and accident-prone
- Difficulty walking due to problems lifting feet from ground
- Dropping forward of toes when feet are lifted from the ground
The initial signs of CMT disease are usually more obvious in the lower extremities and the upper limbs are more affected in later stages of the disease.
Weakness in the feet and legs may lead to slight difficulty in walking and frequent tripping, resulting in recurrent falls and sprains of the ankles.
The main signs and symptoms may include:
- Muscle weakness in the feet, ankles and legs
- Highly arched or very flat feet
- Hammer toes (curled toes)
- Abnormal movement control of the ankle, increasing difficulty to walk
- Decreased or lack of sensation in feet or arms
- Poor circulation to hands and feet
- Cold extremities
- Sensory loss in extremities
Wasting and weakness of the proximal lower leg muscles is common, particularly in patients with type CMT1A. This can lead to a change in appearance of the legs, similar to an inverted champagne bottle. This may also affect the hands and forearms to a lesser extent. Additionally, fatigue can present due to increased effort to make everyday movements.
Some patients also develop tremor, curvature of the spine known as scoliosis and difficulty speaking or swallowing, known as dysphagia.
Most patients do not report symptoms of numbness, despite lacking sensation in the feet and hands, although this may be because they are not aware that sensation should be felt, due to the chronic nature of the symptoms. Some patients do, however, report pain.
As the progression of the disease continues, patients with CMT are likely to notice more advanced symptoms, such as muscle weakness and lack of sensation in the extremities of the limbs.
In later stages of the disease, the upper limbs begin to be more affected, which can decrease hand strength and make fine motor tasks such as writing or buttoning up a shirt more difficult.
Continuing issues with posture and difficulty moving and stress the body, leading to muscle and joint pain. Additionally, damage to the nerves can also sometimes result in neuropathic pain.
As affected individuals get older, the symptoms of CMT disease tend to get progressively more severe. Most individuals are able to continue walking throughout their lifetime, but many will require a walking aid in later stages of the disease.