CMT 1A: Diabetes mellitus exacerbates motor and sensory impairment in

[Guest guest]

J Peripher Nerv Syst. 2008 Dec;13(4):299-304.

Diabetes mellitus exacerbates motor and sensory impairment in CMT1A.

Sheth S, Francies K, Siskind CE, Feely SM, RA, Shy ME.

Department of Neurology and Center for Molecular Medicine and

Genetics, Wayne State University, Detroit, MI, USA.

Charcot-Marie-Tooth disease type 1A (CMT1A) is caused by a

duplication of PMP22 on chromosome 17 and is the most commonly

inherited demyelinating neuropathy.

Diabetes frequently causes predominantly sensory neuropathy. Whether

diabetes exacerbates CMT1A is unknown.

We identified 10 patients with CMT1A and diabetes and compared their

impairment with 48 age-matched control patients with CMT1A alone.

Comparisons were made with the Charcot-Marie-Tooth disease (CMT)

neuropathy score (CMTNS) and by electrophysiology. The CMTNS was

significantly higher in patients with diabetes (20.25 +/- 2.35)

compared with controls (15.19 +/- 0.69; p = 0.01). Values were

particularly higher for motor signs and symptoms. Seven of the 10

diabetic patients had CMTNS >20 (severe CMT), while only 7 of the 48

age-matched controls had scores >20.

There was a trend for CMT1A patients with diabetes to have low

compound muscle action potentials and sensory nerve action

potentials, although nerve conduction velocities were not slower in

diabetic patients compared with controls. Diabetes was associated

with more severe motor and sensory impairment in patients with CMT1A.