Coexistence of Charcot Marie Tooth disease type 1A and diabetes in Taiwan: A clinicopathological study.
BACKGROUND
Charcot Marie Tooth disease type 1A (CMT1A) is the most commonly inherited demyelinating polyneuropathy with variable phenotypes, affected by several comorbidities, especially diabetes mellitus (DM). Previous studies showed that DM exacerbates the clinical manifestations of CMT1A.


METHODS
We retrospectively evaluated patients with CMT1A in our hospital, and identified three groups among 12 cases, which comprised four patients with CMT1A, four with CMT1A+DM, and four with DM. We reviewed the CMT neuropathy score (CMTNS), electrophysiological data, and histomorphological parameters of the sural nerve, including fiber density, myelin thickness, axon diameter, g-ratio, regenerative clusters, and regeneration ratio.


RESULTS
The CMTNS was significantly higher in patients with CMT1A+DM (21.5±2.52) than in those with CMT1A only (10.8±4.4; p=0.03). Pathological findings in patients with CMT1A+DM included a significant decrease of myelinated fiber density (p=0.02) and reduction in the regenerative ratio (p=0.01), indicating severe degeneration with impaired regeneration. In non-parametric analyses, DM was found to play a more important role than CMT1A in influencing nerve degeneration and regeneration.


CONCLUSIONS
In patients with CMT1A, DM exacerbated clinical and pathological manifestations including increased loss of myelinated fibers, abnormal axon-myelin interaction, and impaired nerve regeneration.
Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
Hua-Chuan
HC
Chao
Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
Cheng-Ta
CT
Chou
Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC; Brain Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC.
Yi-Chung
YC
Lee
Department of Neurology, Taipei Veterans General Hospital, Taipei, Taiwan, ROC; Department of Neurology, National Yang-Ming University School of Medicine, Taipei, Taiwan, ROC. Electronic address: kplin@vghtpe.gov.tw.
Kon-Ping
KP
Lin
D000328:Adult; D000368:Aged; D001369:Axons / Q000473:pathology; D002607:Charcot-Marie-Tooth Disease / Q000150:complications / Q000473:pathology*; D003920:Diabetes Mellitus / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009186:Myelin Sheath / Q000473:pathology*; D012189:Retrospective Studies; D013497:Sural Nerve / Q000473:pathology*; D013624:Taiwan; D055815:Young Adult
CMT1A; Charcot–Marie–Tooth disease; Diabetes; Morphometry; Myelin; Peripheral myelin protein 22; Sural nerve biopsy