Guest guest Posted January 26, 2000 Report Share Posted January 26, 2000 << it just hits a raw nerve every time I read anything regarding CMT that states (PAINLESS) >> Thanks for pointing that out. We can't be reminded too often that half of CMTers do suffer from significant pain. I am one who has the pain, also. I will edit that out on my master and put in ... instead. Kat Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 26, 2000 Report Share Posted January 26, 2000 Re: Genetics - more >From: KathleenLS@... > Kat, I know this was taken from the site you posted here, and not your words so this is about the site, it just hits a raw nerve every time I read anything regarding CMT that states (PAINLESS) !! I see this so often and yet the studies have shown there is pain with some CMT individuals. I wish for the sake of newly diagnosed CMT patients that these sites would do some updating of current information. Sorry but had to vent on this subject! P.S. hope you are over your flu/cold bug. >More notes about the genetics of CMT - the syndrome. > >http://www.geneclinics.org/ > >Disease characteristics. Charcot-Marie-Tooth (CMT) Hereditary Neuropathy >refers to a group of disorders that are genetic and produce a chronic motor >and sensory polyneuropathy. The typical patient has distal muscle weakness >and atrophy often associated with mild to moderate sensory loss, depressed >tendon reflexes, and high-arched feet. > >Diagnosis/testing. The genetic neuropathies need to be carefully >distinguished from the many causes of acquired (non-genetic) neuropathies. >Clinical diagnosis is based on family history and characteristic findings on >physical examination, EMG/NCV testing, and occasionally on sural nerve >biopsy. DNA-based clinical/commercial testing is available for three types of >CMT: CMT1A (17p11 duplication), HNPP (17p11 deletion), and CMTX (connexin >32). > >Genetic counseling. The CMT syndrome can be inherited in an autosomal >dominant, autosomal recessive, or X-linked manner. Genetic counseling and >risk assessment depend on a careful determination of the specific CMT subtype. > >---------- >Diagnosis >Establishing the correct diagnosis for a given patient involves a medical >history, physical examination, and neurologic examination, as well as a >detailed family history and the use of DNA-based testing. > >Family history. A three-generation family history with attention to other >relatives with neurologic signs and symptoms should be obtained. >Documentation of relevant findings in relatives can be accomplished either >through direct examination of those individuals or review of their medical >records, including the results of DNA-based testing and EMG studies. Patients >with CMT may have a negative family history for many reasons, including mild >subclinical expression in other family members, recessive inheritance, a new >mutation for a dominant gene, and false paternity. > >Clinical findings. Painless, symmetric, slowly progressive motor neuropathy >of the arms and legs beginning in the 1st-3rd decade with a positive family >history suggests CMT. The acute onset of painless, focal sensory/motor >neuropathy in a single nerve with a history of other affected family members >suggests HNPP. Sudden onset of pain and weakness in the shoulder or upper arm >associated with distal and/or proximal weakness and atrophy of the upper >extremity with other similarly affected family members suggests Familial >Brachial Plexus Neuropathy. Typical CMT patients have high-arched feet, weak >ankle dorsiflexion, thin distal muscles, depressed tendon reflexes, and >distal sensory loss. In CMT1, the most common variety, NCV's are very slow >and peripheral nerves may be palpably enlarged. > >DNA-based testing. DNA-based tests are presently clinically available for >CMT1A, CMTX, and HNPP. DNA-based testing to assess the number of PMP-22 genes >detects >95% of patients with CMT1A (who have 3 copies of the gene) and ~100% >of patients with HNPP (who have 1 copy of the gene). Patients with CMTX have >identifiable mutations in the connexin 32 gene. > >Test strategies for patients with CMT. In families with at least >two-generation involvement, known male-to-male transmission, and slow NCV, >the CMT1A test should be obtained. In families with at least two-generation >involvement but without male-to-male transmission, the CMT1A and CMTX DNA >tests should be done sequentially. In families with apparent X-linked >inheritance of the CMT phenotype, mutation analysis of the connexin 32 gene >is appropriate in order to confirm the diagnosis. > >In sporadic cases, the first step is to exclude potential acquired causes of >neuropathy by standard neurological evaluation. Both CMT1A and CMTX DNA tests >should be performed on males and females who are sporadic cases, because new >duplications of the 17p11 region often occur and because female carriers of a >connexin 32 disease-causing mutation may be symptomatic. > >Negative DNA testing results for the PMP-22 gene and connexin 32 gene cannot >correctly rule out a diagnosis of CMT since those test results may be >compatible with an undetected point mutation in PMP-22, CMT1B, CMT1C, CMT2, >or some other form of hereditary neuropathy. > >The HNPP DNA test in which a deletion of the PMP-22 gene is present (such >that affected individuals have only one copy of the gene) is also clinically >available and should be obtained in individuals with recurrent pressure >palsies. > >--------------------------- Quote Link to comment Share on other sites More sharing options...
Guest guest Posted January 26, 2000 Report Share Posted January 26, 2000 Re: Genetics - more >From: KathleenLS@... > Kat, I know this was taken from the site you posted here, and not your words so this is about the site, it just hits a raw nerve every time I read anything regarding CMT that states (PAINLESS) !! I see this so often and yet the studies have shown there is pain with some CMT individuals. I wish for the sake of newly diagnosed CMT patients that these sites would do some updating of current information. Sorry but had to vent on this subject! P.S. hope you are over your flu/cold bug. >More notes about the genetics of CMT - the syndrome. > >http://www.geneclinics.org/ > >Disease characteristics. Charcot-Marie-Tooth (CMT) Hereditary Neuropathy >refers to a group of disorders that are genetic and produce a chronic motor >and sensory polyneuropathy. The typical patient has distal muscle weakness >and atrophy often associated with mild to moderate sensory loss, depressed >tendon reflexes, and high-arched feet. > >Diagnosis/testing. The genetic neuropathies need to be carefully >distinguished from the many causes of acquired (non-genetic) neuropathies. >Clinical diagnosis is based on family history and characteristic findings on >physical examination, EMG/NCV testing, and occasionally on sural nerve >biopsy. DNA-based clinical/commercial testing is available for three types of >CMT: CMT1A (17p11 duplication), HNPP (17p11 deletion), and CMTX (connexin >32). > >Genetic counseling. The CMT syndrome can be inherited in an autosomal >dominant, autosomal recessive, or X-linked manner. Genetic counseling and >risk assessment depend on a careful determination of the specific CMT subtype. > >---------- >Diagnosis >Establishing the correct diagnosis for a given patient involves a medical >history, physical examination, and neurologic examination, as well as a >detailed family history and the use of DNA-based testing. > >Family history. A three-generation family history with attention to other >relatives with neurologic signs and symptoms should be obtained. >Documentation of relevant findings in relatives can be accomplished either >through direct examination of those individuals or review of their medical >records, including the results of DNA-based testing and EMG studies. Patients >with CMT may have a negative family history for many reasons, including mild >subclinical expression in other family members, recessive inheritance, a new >mutation for a dominant gene, and false paternity. > >Clinical findings. Painless, symmetric, slowly progressive motor neuropathy >of the arms and legs beginning in the 1st-3rd decade with a positive family >history suggests CMT. The acute onset of painless, focal sensory/motor >neuropathy in a single nerve with a history of other affected family members >suggests HNPP. Sudden onset of pain and weakness in the shoulder or upper arm >associated with distal and/or proximal weakness and atrophy of the upper >extremity with other similarly affected family members suggests Familial >Brachial Plexus Neuropathy. Typical CMT patients have high-arched feet, weak >ankle dorsiflexion, thin distal muscles, depressed tendon reflexes, and >distal sensory loss. In CMT1, the most common variety, NCV's are very slow >and peripheral nerves may be palpably enlarged. > >DNA-based testing. DNA-based tests are presently clinically available for >CMT1A, CMTX, and HNPP. DNA-based testing to assess the number of PMP-22 genes >detects >95% of patients with CMT1A (who have 3 copies of the gene) and ~100% >of patients with HNPP (who have 1 copy of the gene). Patients with CMTX have >identifiable mutations in the connexin 32 gene. > >Test strategies for patients with CMT. In families with at least >two-generation involvement, known male-to-male transmission, and slow NCV, >the CMT1A test should be obtained. In families with at least two-generation >involvement but without male-to-male transmission, the CMT1A and CMTX DNA >tests should be done sequentially. In families with apparent X-linked >inheritance of the CMT phenotype, mutation analysis of the connexin 32 gene >is appropriate in order to confirm the diagnosis. > >In sporadic cases, the first step is to exclude potential acquired causes of >neuropathy by standard neurological evaluation. Both CMT1A and CMTX DNA tests >should be performed on males and females who are sporadic cases, because new >duplications of the 17p11 region often occur and because female carriers of a >connexin 32 disease-causing mutation may be symptomatic. > >Negative DNA testing results for the PMP-22 gene and connexin 32 gene cannot >correctly rule out a diagnosis of CMT since those test results may be >compatible with an undetected point mutation in PMP-22, CMT1B, CMT1C, CMT2, >or some other form of hereditary neuropathy. > >The HNPP DNA test in which a deletion of the PMP-22 gene is present (such >that affected individuals have only one copy of the gene) is also clinically >available and should be obtained in individuals with recurrent pressure >palsies. > >--------------------------- Quote Link to comment Share on other sites More sharing options...
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