Hereditary neuropathy with pressure palsies (HNPP)
What's the cause?
We needtwo PMP22 genes, one from each parent, for the normal development of the peripheral nerves.These genesprovide instructions for the creation of PMP22 protein, whichmakes uptheprotective outer layer of each nerve. This outer layer, which is a bit liketheplastic coating that insulates a wire,is called myelin.
InHNPP, one copy of the PMP22 gene is lost (deleted) so that people have only one copy of this gene. A person with HNPP will have inherited a faulty copy of the PMP22 genefrom one of their parents.
With onlyone normal PMP22 gene,their myelin is fragile and more susceptible to injury.Just the slightest pressure, stretch or repetitive movement on the nervecauses sections of the myelin to be lost, leading to muscle weakness or "pressure palsies". Signals cannot be relayed to and from the muscles properly.
Medically Reviewed by a doctor on 21 Dec 2018
Introduction
Hereditary neuropathy with pressure palsies (HNPP) is an inherited nerve disorder that typically causes numbness, tingling and muscle weakness.
What are the symptoms of HNPP?
HNPPranges in severity some people get no symptoms at all or find it a minor nuisance, while others are so badly affected they can't even move the affected limb. Most people with HNPP have attacks o
What's the cause?
We needtwo PMP22 genes, one from each parent, for the normal development of the peripheral nerves.These genesprovide instructions for the creation of PMP22 protein, whichmakes uptheprotective outer la
How is it diagnosed?
A diagnosis of HNPP is based on symptoms(such asrecurrent loss of sensation in one particular area), evidence of a family history and electrical nerve tests. A genetic test will confirm the diagnosis.
How is it managed?
There's currently no cure for HNPP, but some of the symptoms can be treated, and lifestyle changes can make a huge difference. Lifestyle advice Ifyou can feel anywarning signs (such as tingling),sto
More information and support
HNPP.org HNPP UK Hereditary Neuropathy Foundation CMT UK
Subscribe
Ask the doctor
Rate this article
Find products