HNPP

同: hereditary neuropathy with liability to pressure palsies

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/07/08 06:00:10」(JST)

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Hereditary Neuropathy with Liability to Pressure Palsy (HNPP) is a peripheral neuropathy (disorder of the nerves).

Nerve with myelin sheath

General description

HNPP is a nerve disorder that affects the peripheral nerves. The main effect of HNPP are pressure palsies. Pressure on the nerves can cause tingling sensations, numbness, pain, weakness, muscle atrophy, and even paralyzation of affected area.

In normal individuals these symptoms disappear quickly but in sufferers of HNPP even a short period of pressure can cause the symptoms to occur. These usually subside over an extended period of time. Palsies can last from minutes, day to weeks or even months or years. However repeated incidents can cause permanent muscle weakness.

HNPP evolves slowly with symptoms surfacing between usually in the late teens to early twenties (range 8 to 64 years).^[1]

The symptoms vary from person to person. Some report minor problems, whilst others experience severe discomfort and a moderate disability. In many cases the symptoms are mild enough to go unnoticed. The time period between episodes is known to vary between individuals. HNPP has not been found to alter the lifespan, although in some cases a decline in quality of life is noticed.

Some sufferers (10-15%) report various pains growing in severity with progression of the disease.^[2]

The nerves most commonly affected are the peroneal nerve at the fibular head (leg and feet), the ulnar nerve at the elbow (arm) and the median nerve at the wrist (palm, thumbs and fingers).

HNPP is part of the group of Hereditary Motor and Sensory Neuropathy (HMSN) and is linked to Charcot–Marie–Tooth disease (CMT).

Diagnosis

Measuring nerve conduction velocities may give an indication of the presence of the disease, but HNPP can only be diagnosed by a genetic blood test. For fingers, it is often confused with carpal tunnel syndrome.

Symptoms

Back Pain
Pain at the sites of entrapment
Leg/ankle foot swelling
Fatigue
Muscle cramps
Paresthesias (abnormal sensations)
Muscle weakness
Foot drop
Numbness in fingers
Numbness in toes causing loss of balance

Causes

HNPP is an autosomal dominant genetic disease. A mutation in one copy of the gene PMP-22 (Peripheral myelin protein 22, 17p11.2) that makes the peripheral myelin protein causes haploinsufficiency, where the activity of the normal gene is insufficient to compensate for the loss of function of the other gene. The lack of myelin causes the nerves to be poorly insulated and it is this that causes symptoms. On visualization the nerves have a sausage like appearance that blocks the nerve signals (hence the name 'tomaculous neuropathy' that is sometimes used for HNPP).

Both male and females are equally affected. A child has a 50% chance of inheriting the disease if one parent is a sufferer of the disease. It is estimated that it occurs in 2 to 5 in 100000 individuals.

Nervous system : peroneal, ulnar and median nerve

Cure

Currently there are no effective treatments but it is a possible candidate for gene therapy. Currently simple adjustments to the individuals lifestyle are the best treatment in order to avoid excess pressure on the nerves. Avoiding repetitive injury of a nerve is important, as this makes the symptoms worse. To reduce foot and leg swelling, lying with feet raised above hip level is recommended. For fingers, splints keeping the wrist and pals aligned can be prescribed for night use. Avoiding sleeping in foetal position is useful for all symptoms.

Common problems

There are lots of common problems, mainly caused by focused pressure on the nerves :

Kneeling
Cutting with scissors
Holding plastic grocery bags (or carrying anything that gives high pressure on one point)
Sitting with legs crossed
Leaning on elbows, forearms or wrists
Sleeping in the 'wrong' positions
Sitting too long in the same position
Walking in high heels
Being in the front leaning rest

History

Inherited peripheral nerve disorders were first described by Charcot, Marie and Tooth (1886). De Jong (1947) first described HNPP in a Dutch family. Dyck and Lambert (1968) showed nerve conduction slowing in families using electrophysiological studies. Chance et al. (1993) detected the chromosome deletion in most of the patients with HNPP.

External links

GeneReviews/NCBI/NIH/UW entry on Hereditary Neuropathy with Liability to Pressure Palsies
General Information about HNPP : HNPP.org
General Information about HNPP: HNPP UK
'Rare disease means I may wake up unable to move' (case study): BBC News

References

^ Gilbert, Brigitte (May 2004). "Hereditary Neuropathy with Liability to Pressure Palsies" (PDF). p. 4.
^ "Hereditary Neuropathy with Liability to Pressure Palsies". April 2007.

UpToDate Contents

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1. 遺伝性ニューロパチーの概要 overview of hereditary neuropathies
2. シャルコーマリートゥース病などの一次性の遺伝性運動感覚性ニューロパチー hereditary primary motor sensory neuropathies including charcot marie tooth disease
3. 慢性炎症性脱髄性多発神経炎：病因、臨床的特徴、および診断 chronic inflammatory demyelinating polyneuropathy etiology clinical features and diagnosis
4. ゲノム疾患：概要 genomic disorders an overview
5. 手根管症候群の病因 etiology of carpal tunnel syndrome

English Journal

Hereditary neuropathy with liability to pressure palsies in childhood: Case series and literature update.

Chrestian N1, McMillan H2, Poulin C3, Campbell C4, Vajsar J5.
Neuromuscular disorders : NMD.Neuromuscul Disord.2015 Sep;25(9):693-8. doi: 10.1016/j.nmd.2015.06.463. Epub 2015 Jun 30.
Hereditary Neuropathy with Liability to Pressure Palsy (HNPP) is a rare condition in childhood with a diverse range of clinical presentations. We analyzed the clinical presentation and electrophysiological data of 12 children with a confirmed PMP22 gene deletion and reviewed the published reports of
PMID 26189194

An n-of-one RCT for intravenous immunoglobulin G for inflammation in hereditary neuropathy with liability to pressure palsy (HNPP).

Vrinten C1, Gu X2, Weinreich SS3, Schipper MH4, Wessels J5, Ferrari MD6, Hoijtink H2, Verschuuren JJ6.
Journal of neurology, neurosurgery, and psychiatry.J Neurol Neurosurg Psychiatry.2015 Jul 17. pii: jnnp-2014-309427. doi: 10.1136/jnnp-2014-309427. [Epub ahead of print]
PMID 26187721

Distinctive patterns of sonographic nerve enlargement in Charcot-Marie-Tooth type 1A and hereditary neuropathy with pressure palsies.

Goedee SH1, Brekelmans GJ2, van den Berg LH3, Visser LH2.
Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology.Clin Neurophysiol.2015 Jul;126(7):1413-20. doi: 10.1016/j.clinph.2014.08.026. Epub 2014 Oct 12.
OBJECTIVE: The extent of sonomorphologic differences of peripheral nerves between CMT and HNPP is unknown.METHODS: We recruited 9 patients with CMT-1A and 9 with HNPP. Patients underwent a standardized sonographic protocol, which evaluated nerve size and vascularization. We quantitatively assessed f
PMID 25454274

Japanese Journal

Thermal Conductivity of Size-Controlled Bulk Silicon Nanocrystals Using Self-Limiting Oxidation and HF Etching

Suzuki Takayuki,Ohishi Yuji,Kurosaki Ken [他],Muta Hiroaki,Yamanaka Shinsuke
Applied Physics Express 5(8), 081302-081302-3, 2012-08-25
… In this method, which we call ``HF-etching nanosize-controlling process for powder (HNPP), self-limiting oxidation coupled with HF etching is applied to nanopowder Si. … The application of HNPP to nanopowder Si reduces the average diameter from 58 to 35 nm. …
NAID 40019394598

Hereditary neuropathy with liability to pressure palsy (HNPP) in childhood : A case study emphasizing the relevance of detailed electrophysiological examination for suspected HNPP in the first decade

BAYRAK Ayse Oytun,BATTALOGLU Esra,TURKER Hande,BARIS Ibrahim,OZTAS Gurkan
Brain & development 31(6), 445-448, 2009-06-01
NAID 10025580349

Charcot-Marie-Tooth 病の眼球運動について

菅澤恵子,内藤理恵,渡辺由季,室伏利久
Equilibrium research 65(4), 245-251, 2006-08-01
… Brain MRI demonstrated slight cerebellar atrophy in only one case and no apparent abnormality in the other six cases.<BR>No abnormal eye movement was found in two patients with CMT type 1, but some abnormal eye movements were surprisingly observed in five patients including one with CMT type 1, three with CMT type 2, and one with HNPP. …
NAID 10021289551