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Genetic epidemiology of Charcot–Marie–Tooth in the general population
Author(s) -
Braathen G. J.,
Sand J. C.,
Lobato A.,
Høyer H.,
Russell M. B.
Publication year - 2011
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/j.1468-1331.2010.03037.x
Subject(s) - medicine , population , geneticist , epidemiology , peripheral myelin protein 22 , genetics , genetic epidemiology , genotype , point mutation , gene , mutation , gene duplication , biology , environmental health
Background and purpose: The frequency of different Charcot–Marie–Tooth (CMT) genotypes has been estimated in clinic populations, but prevalence data from the general population are lacking. Methods: Our population‐based genetic epidemiological survey included persons with CMT residing in eastern Akershus County, Norway. The participants were interviewed and examined by one geneticist/neurologist and classified clinically, neurophysiologically and genetically. Results: Two hundred and forty‐five persons from 116 families had CMT. This corresponds to 1 per 1214 persons (95% CI 1062–1366) have CMT in the general population. CMT1 (motor conduction velocity (MCV) <38 m/s), CMT2 (MCV >38 m/s) and CMT intermediate (MCV 25–45 m/s) were found in 48.2%, 49.4% and 2.4% of the families. A total of 27.2% of the families and 28.6% of the affected had a mutation in the investigated CMT genes. The prevalence of the peripheral myelin protein 22 ( PMP22 ) duplication and point mutation in the connexin32 ( Cx32 ), myelin protein zero ( MPZ ) and mitofusin2 ( MFN2 ) genes was found in 13.6%, 6.2%, 1.2%, 6.2% of the families, and in 19.6%, 4.8%, 1.1%, 3.2% of the affected, respectively. None of the families had point mutations in the early growth response 2 ( EGR2 ), PMP22 or small integral membrane protein of lysosome/late endosome ( SIMPLE ) genes. Conclusions: CMT is the most common inherited neuropathy. At present, 43 CMT genes are known, and an examination of all known genes would probably only identify mutations in approximately 50% of those with CMT. Thus, it is probable that at least 30–50 CMT genes are yet to be identified.