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It's In The Genes
By Jennifer Bradley, Staff Writer

(Page 2 of 4)


Hereditary Neuropathy with Liability to Pressure Palsies (HNPP) is the second major type of hereditary neuropathy.

It is also a slow progressing disease and common, but less diagnosed than CMT. People with HNPP experience episodes of numbness and weakness, brought on by fairly mild pressure or trauma to a single nerve. Each episode of numbness may last for several minutes, to several days or months. Two or three months are the most common time periods for symptoms to last, but those diagnosed have reported 6 to 12 months as well. The symptoms are found to occur prevalently in the wrists, elbows and knees.

In 90 percent of people, HNPP causes carpal tunnel syndrome.

The symptoms and severity can vary greatly from individual to individual; many people do not even know they have HNPP. The numbness may be as mild as someone noticing an arm or leg doesnít have quite the same feeling or, it could be as severe that it feels like itís been numbed with Novocain. The same scale goes for weakness, varying from slight to unable to move an arm or leg.

Those living with HNPP, as with CMT, do not have a lessened life expectancy.
A third type of hereditary neuropathy is familial dysautonomia, or Riley-Day syndrome. Itís prevalent in Jews of European descent, also affecting both autonomic and sensory nerves.

In Riley-Day patients, symptoms will be noticeable in a personís infancy. A baby may have difficulty feeding because of decreased muscle tone. The child also will have problems producing tears, and less-than-normal pain and temperature sensitivity.

A childís sense of taste is altered with Riley-Day syndrome. In addition to a young child holding his or her breath, they also struggle with blood pressure. This leads to dizziness and fainting. Learning disabilities are common as well.
Unlike other forms of hereditary neuropathy, loved ones with Riley-Day have a greatly reduced life expectancy.

How do you know?

If a loved one is suspected of having a hereditary neuropathy, theyíll undergo an extensive neurological exam and workup. This will include the following:

  • Complete health history
    Itís important a neurologist learns when the symptoms started, their severity, duration, location, what relieves them, etc.  
  • Neurological evaluation
    This is a physical examination of reflexes, strength and ability to feel sensations, in addition to evaluation of autonomic nervous system.


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