diagnostic problem of charcot-marie-tooth disease
نویسندگان
چکیده
diseases of the motor unit are common in children. these diseases are mostly genetically determined. cmt represents a clinically heterogeneous group of disorders caused by aberration of the intimate relationship between the schwann cell sheath and the neural axon, ultimately resulting in axonal death and muscular dennervation. a simple clinical classification of cmt (demyelinating versus axonal) improves the yield of genetic testing and determines which genes should be tested for. when deciding on genetic testing, one should consider multiple factors including (1) availability of clinical testing, (2) the yield of a specific molecular test, (3) the aim of establishing a molecular diagnosis, and (4) in sporadic cases, the frequency of de novo mutation. molecular tools have increased the possibility of establishing a specific diagnosis. the most common mutations of cmt are (1) axonal type: a-ad (mfn2, mpz mut) b-ar (gdap1 mut) c-x linked (gjb1) (2) demyelinating: a-ad (pmp22 dup, mut-mpz mut) b-ar (prx, gdpa1 mut) c-x linked (gjb1). in the demyelinating form, the combination of cmt1a duplication and cx32 mutation testing has a yield of approximately 80%. mpz and pmp22 mutations are the next most common culprits. in cases of axonal cmt, cx32 mutations are followed by mpz mutations in the population-based studies. for unaffected parents with a child affected with cmt1 or cmt2, four possibilities exist: a de novo dominant mutation in the affected child, ar inheritance, xl inheritance, or nonpaternity. an affected parent with ad or xl- dominant cmt1 or cmt2 has 50% risk of having a child with the same mutation. due to limitations of molecular tools in our country, the best suggestion in genetic counseling is to avoid intrafamily marriages.
منابع مشابه
Charcot-Marie-Tooth disease
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Charcot-Marie-Tooth (CMT) disease is the most prevalent peripheral inherited neuropathy (1/2500 to 10 000; 2.8/10 000 in Spain), and the mean age at onset is 16 years (range 2 to 50 years, but presentation in the early infancy and as late as the 80's has been reported). Patients present with motor and sensory polyneuropathic semiology (distal lower limb weakness and atrophy, gait abnormalities ...
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عنوان ژورنال:
genetics in the 3rd millenniumجلد ۷، شماره ۳، صفحات ۱۸۳۸-۱۸۳۹
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