What is hereditary neuropathy?
A hereditary neuropathy is an inherited (runs in families) disorder of the peripheral nervous system (nerves away from the brain and spinal cord). There are many different hereditary neuropathies.
Symptoms of a hereditary neuropathy may include:
- Muscle weakness (especially in the foot and leg)
- Foot deformities
- Muscle wasting (shrinking and weakness) in the legs
- Curved spine
- Loss of pain sensitivity
A hereditary neuropathy is diagnosed with nerve conduction studies (tests of how well your nerves conduct electrical signals), nerve biopsies (looking at a sample of nerve tissue under a microscope) and genetic testing. A neurologist (doctor specializing in nervous system disorders) will also take a complete medical history and do a complete physical examination.
A hereditary neuropathy may be diagnosed as early as birth or as late as middle age or older. Charcot-Marie-Tooth (CMT) disorder is the most common type of hereditary neuropathy.
Symptoms of hereditary neuropathy
The most common hereditary neuropathy is Charcot-Marie-Tooth disorder (CMT). Symptoms include:
- High foot arches or extremely flat feet
- Other foot deformities, such as hammertoes (curled toes)
- Muscle wasting (muscles shrink and get weaker) that gets worse over time
- Problems with walking, running and balance
- Scoliosis (curved spine) or hip dysplasia (dislocated hip)
- Weak ankles (ankle sprains are common)
- Foot drop (difficulty lifting your foot at the ankle)
- Tingling and burning sensations in hands or feet
- Loss of sensation, dry skin or hair loss in affected areas of the body
If CMT causes nerve pain, you may need medication. Loss of nerve sensation can lead to cutting or burning yourself without realizing it. In a few people, loss of nerve sensation causes hearing loss and sometimes deafness.
As CMT develops, it can affect hand function. The hand muscles may atrophy (shrink and get weaker) and people with CMT can lose the ability to pinch things between the thumb and fingers. This can cause problems with:
- Holding a pencil or penButtoning or zipping clothes
- Turning doorknobs
If you or a loved one has CMT, occupational therapy can help you find ways to do difficult things. The right equipment can make many tasks easier.
Other symptoms of CMT
Even though CMT can cause loss of nerve sensation, some people with CMT are very sensitive to the cold or even to temperatures a few degrees lower than normal. Losing muscle mass, muscle activity and circulation can cause cold hands and feet. Loss of normal circulation can also cause foot and ankle swelling.
Some people with CMT lose reflexes such as the knee jerk reaction. Some have tremor (shaking), usually of the hands. The combination of tremor and CMT is sometimes called Roussy-Levy syndrome.
Weakness of the respiratory (breathing) muscles is rare in people with CMT, but when it happens, it can cause life-threatening problems. If someone with CMT is short of breath, he or she should see a respiratory specialist to see if a ventilator (automatic breathing machine) would help.
Symptoms of CMT can be very different for each patient, even in the same family. A child may have more or fewer symptoms than his or her parent. Some family members may be disabled and need to wear braces while others have no noticeable symptoms, even if a doctor's examination, EMG tests or nerve conduction studies show they have CMT.
Prognosis for people with CMT
The prognosis for people with hereditary neuropathy depends on the symptoms. Some types of hereditary neuropathy (CMT) progress (get worse) more slowly than other types.
At the OHSU ALS and Neuromuscular Disease Center, we provide the most advanced treatment for hereditary neuropathy. We bring experts from around OHSU together to give you the best care available.