Genetic epidemiology of CMT in the general population

[Guest guest]

Eur J Neurol. 2010 May 5.

Genetic epidemiology of Charcot-Marie-Tooth in the general population.

Braathen GJ, Sand JC, Lobato A, Høyer H, MB.

Faculty Division Akershus University Hospital, University of Oslo, Nordbyhagen,

Oslo.

Abstract

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.

[Guest guest]

Finally, we get some current statistics! Interesting how this comes out of

Norway, I think the 1974 study did too.

Gretchen

> This corresponds to 1 per 1214 persons have CMT in the general population>