Guest guest Posted February 11, 2001 Report Share Posted February 11, 2001 http://www.charcot-marie-tooth.org/hnpp.htm What is HNPP? By Maureen Horton Edited by Dr. Chance, the CMTA Medical Advisory Board (Editor's note: The CMTA will be working with Maureen to keep our readership updated on HNPP. She has HNPP and first noticed problems during her pregnancies. She was finally diagnosed with HNPP and because information was so difficult to find, she began to teach herself about the disorder. As a nurse, Maureen offers our readers both the personal side of the disorder and medical expertise on the subject.) Hereditary neuropathy with liability to pressure palsies or HNPP is associated with a deletion on chromosome 17p11.2-12. This is the same chromosomal site where CMT1A has been found to have a duplication, and it contains an important myelin gene, peripheral myelin protein-22 gene (PMP22). Therefore, while CMT1A results from having an extra copy of PMP22, HNPP results from the loss of a copy of PMP22. HNPP is caused by an autosomal dominant gene. HNPP is also a demyelinating form of neuropathy like CMT1A. However, the affected nerves in HNPP are described as having focal regions with " tomaculous " changes or sausage shaped figures, due to the irregular thickening of the myelin sheath. HNPP causes episodes or periods of numbness and weakness, similar to an arm or leg going to sleep. But, instead of lasting only a few seconds, as it does in a normal person, this numbness and weakness can last from several minutes to months. These episodes may be associated with fairly mild trauma (stretching or pressure on the nerves) which would not ordinarily affect a normal person, such as: leaning on elbows, crossing legs, cutting with scissors, knitting, kneeling, sleeping in the wrong position, etc. It has usually been described as a painless disorder, although some people do have pain, which is probably a subjective sense of numbness. Most individuals with HNPP have normal strength and sensation, unless experiencing an attack. Typically, persons who have inherited HNPP will develop symptoms in their teens or twenties, but individuals may be first symptomatic during childhood or late adulthood. Like CMT, there is a wide range in how severely people are affected. Many are so mild that they are unaware that they have a problem. Others develop the symptoms of a more generalized hereditary motor and sensory neuropathy, which on occasion may be misdiagnosed as a form of CMT. Carpal tunnel syndrome is frequently seen in patients with HNPP. As a hereditary neuropathy it is progressive, though to what extent it will progress in any individual is unknown. There is no treatment or cure for HNPP. People are usually advised to avoid activities which they have learned cause symptoms to develop. Leg crossing and leaning on elbows is discouraged. AFOs can be used during periods of acute peroneal nerve palsy or for permanent foot drop and/or balance problems. For more information on HNPP, please visit www.hnpp.org. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 11, 2001 Report Share Posted February 11, 2001 In a message dated 2/11/01 11:06:16 AM, rmax@... writes: << >>>>>>>Kat so this says that HNPP is not a " form " of CMT? >> " Therefore, while CMT1A results from having an extra copy of PMP22, HNPP results from the loss of a copy of PMP22. " They are genetic opposites but result in many symptoms in common. I've met many HNPPers in the CMT chat room. As with CMT, we have many similar problems as well as differences. Some people think CMT types 1 and 2 may not actually be properly called CMT for various reasons. For example: I don't have the usual atrophied calves or extremely high arches, but I still have CMT type 2. Some HNPPers DO have atrophied calves and/or extremely high arches. Diagnosing is still in a state of flux and learning. Kat Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 11, 2001 Report Share Posted February 11, 2001 In a message dated 2/11/2001 2:12:39 PM Eastern Standard Time, lisarich.com@... writes: << I'm grateful you posted this, because I didn't really know what the differences were. Thanks. >> As far as symptoms go, there aren't that many differences. Right? Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 11, 2001 Report Share Posted February 11, 2001 In a message dated 2/11/01 12:46:49 PM, lls@... writes: << One thing is certain with CMT, HNPP, HMSN, or whatever-- " We are all connected " >> I agree completely, but I don't think the medical community is finished fine-tuning the labels. Some types of CMT were formerly called other names, for example. Dorothy Gosling, RN, is the person who got me thinking about this. As with your family, they are still learning, and last I heard she didn't fit just one catagory either. I actually was trying to say we are indeed all connected, but there is more to learn. Kat Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 11, 2001 Report Share Posted February 11, 2001 It is my understanding that HNPP is the genetic opposite of only one very specific type of CMT, that being CMT1A. Because there are so many forms of CMT caused by so many identified AND unidentified genes, and because so many CMTers CANNOT have their specific CMT type identified because gene tests are not available for all types, why not include HNPP in our discussion as well??? The problems and coping solutions for HNPP are similar to the problems and coping solutions for the very many different types of CMT. Ruth Warren > Just to clarify for anyone new to - this group is for people > and their families with CMT. CMT and HNPP are NOT the same. They are > exact genetic opposites. Anyone wanting HNPP info can go to > http://www.hnpp.org or hnpp://www..groups.com/group/HNPP Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 11, 2001 Report Share Posted February 11, 2001 -----Original Message----- From: KathleenLS@... <KathleenLS@...> < > Date: Sunday, February 11, 2001 12:21 PM Subject: Re: [] CMT not HNPP >http://www.charcot-marie-tooth.org/hnpp.htm >What is HNPP? >By Maureen Horton > others develop the symptoms of a more generalized hereditary motor and >sensory neuropathy, which on occasion may be misdiagnosed as a form of CMT. > www.hnpp.org. > >>>>>>>Kat so this says that HNPP is not a " form " of CMT? ~>Becky M. Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 11, 2001 Report Share Posted February 11, 2001 I'm grateful you posted this, because I didn't really know what the differences were. Thanks. ----- Original Message ----- From: <KathleenLS@...> < > Sent: Sunday, February 11, 2001 12:23 PM Subject: Re: [] CMT not HNPP > http://www.charcot-marie-tooth.org/hnpp.htm > What is HNPP? > By Maureen Horton > > Edited by Dr. Chance, the CMTA Medical Advisory Board > > (Editor's note: The CMTA will be working with Maureen to keep our readership > updated on HNPP. She has HNPP and first noticed problems during her > pregnancies. She was finally diagnosed with HNPP and because information was > so difficult to find, she began to teach herself about the disorder. As a > nurse, Maureen offers our readers both the personal side of the disorder and > medical expertise on the subject.) > > Hereditary neuropathy with liability to pressure palsies or HNPP is > associated with a deletion on chromosome 17p11.2-12. This is the same > chromosomal site where CMT1A has been found to have a duplication, and it > contains an important myelin gene, peripheral myelin protein-22 gene (PMP22). > Therefore, while CMT1A results from having an extra copy of PMP22, HNPP > results from the loss of a copy of PMP22. > > HNPP is caused by an autosomal dominant gene. HNPP is also a demyelinating > form of neuropathy like CMT1A. However, the affected nerves in HNPP are > described as having focal regions with " tomaculous " changes or sausage shaped > figures, due to the irregular thickening of the myelin sheath. > > HNPP causes episodes or periods of numbness and weakness, similar to an arm > or leg going to sleep. But, instead of lasting only a few seconds, as it does > in a normal person, this numbness and weakness can last from several minutes > to months. These episodes may be associated with fairly mild trauma > (stretching or pressure on the nerves) which would not ordinarily affect a > normal person, such as: leaning on elbows, crossing legs, cutting with > scissors, knitting, kneeling, sleeping in the wrong position, etc. It has > usually been described as a painless disorder, although some people do have > pain, which is probably a subjective sense of numbness. Most individuals with > HNPP have normal strength and sensation, unless experiencing an attack. > > Typically, persons who have inherited HNPP will develop symptoms in their > teens or twenties, but individuals may be first symptomatic during childhood > or late adulthood. Like CMT, there is a wide range in how severely people are > affected. Many are so mild that they are unaware that they have a problem. > Others develop the symptoms of a more generalized hereditary motor and > sensory neuropathy, which on occasion may be misdiagnosed as a form of CMT. > Carpal tunnel syndrome is frequently seen in patients with HNPP. > > As a hereditary neuropathy it is progressive, though to what extent it will > progress in any individual is unknown. There is no treatment or cure for > HNPP. People are usually advised to avoid activities which they have learned > cause symptoms to develop. Leg crossing and leaning on elbows is discouraged. > AFOs can be used during periods of acute peroneal nerve palsy or for > permanent foot drop and/or balance problems. > For more information on HNPP, please visit www.hnpp.org. > > > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 11, 2001 Report Share Posted February 11, 2001 Kat, Over 15 neurologists have diagnosed my various family members with CMT. All genetic tests are negative. Nerve biopsy indicates type 1, nerve conduction indicated Type-2 . In compiling medical records for the research on my family, I have encountered three reports that state " both axonal and demyelinative " . One thing is certain with CMT, HNPP, HMSN, or whatever-- " We are all connected " ----- Original Message ----- From: KathleenLS@... Sent: Sunday, February 11, 2001 02:22 PM Subject: Re: [] CMT not HNPP In a message dated 2/11/01 11:06:16 AM, rmax@... writes: << >>>>>>>Kat so this says that HNPP is not a " form " of CMT? >> " Therefore, while CMT1A results from having an extra copy of PMP22, HNPP results from the loss of a copy of PMP22. " They are genetic opposites but result in many symptoms in common. I've met many HNPPers in the CMT chat room. As with CMT, we have many similar problems as well as differences. Some people think CMT types 1 and 2 may not actually be properly called CMT for various reasons. For example: I don't have the usual atrophied calves or extremely high arches, but I still have CMT type 2. Some HNPPers DO have atrophied calves and/or extremely high arches. Diagnosing is still in a state of flux and learning. Kat Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 12, 2001 Report Share Posted February 12, 2001 They sound awfully close to me. But, I'm no CMT genius either....still learning. ----- Original Message ----- From: <ktbugg54@...> < > Sent: Sunday, February 11, 2001 2:13 PM Subject: Re: [] CMT not HNPP > In a message dated 2/11/2001 2:12:39 PM Eastern Standard Time, > lisarich.com@... writes: > > << I'm grateful you posted this, because I didn't really know what the > differences were. Thanks. > >> > > As far as symptoms go, there aren't that many differences. Right? > > > > Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 12, 2001 Report Share Posted February 12, 2001 >Gretchen, >You make me feel genetically discriminated against by this statement. CMT is >actually a multiplicity of genetic defects most of which we do not have a >clear relationship between symptoms (phenotype) and causes (genotype). Their >is a long way to go to sort that out. In the meantime, as several have >stated, we have similar problems and flock together to help resolve them in >our lives. > >As for me, I know that I have HNPP thanks due to the Athena Labs DNA tests >and am very thankful that is so. The old view that HNPP is only a minor >numbness problem is now dead these past couple of years. Personally, I have >most of the physical deformity and pain problems displayed by CMT1A patients >and strongly consider myself to be under the aegis of CMT in general. In my >book, duplication vs. deletion is not a discriminating factor and only >different forms of genetic defects. The treatments and solutions to the >disease's problems are entirely common to both. When (and not if) we resolve >the phenotype-genotype puzzle, I believe that more deletions and >duplications will be found in the family of CMT diseases and have no >problems with them being identified with the people who discovered them - >Messrs Charcot, Marie, and Tooth. So, what's in a name ? A disease by any >other name would be its same debilitating self. EdM > > >-----Original Message----- >From: Gretchen Glick <liliwigg@...> > < > >Date: Sunday, February 11, 2001 1:08 PM >Subject: [] CMT not HNPP > > >>Just to clarify for anyone new to - this group is for people >>and their families with CMT. CMT and HNPP are NOT the same. They are >>exact genetic opposites. Anyone wanting HNPP info can go to >>http://www.hnpp.org or hnpp://www..groups.com/group/HNPP >> >> >> Quote Link to comment Share on other sites More sharing options...
Guest guest Posted February 12, 2001 Report Share Posted February 12, 2001 Kat, Great point. Some CMT types affect the myelin and others affect the axon. In the end, the nerve is still damaged and subsequently causes a wide range of problems. I like the analogy about the boat! Ruth Warren > This also reminds me that the medical difference between the several type 1 > CMTs and the several type 2 CMTs is another opposite. With type 1 the damage > is on the outside of the nerve and with type 2 the damage is on the inside. > But both are called CMT. Both have similar symptoms. > > We are all in the same boat, just in some of the different sections of it. > > Kat Quote Link to comment Share on other sites More sharing options...
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