Background To collect preliminary data on the effects of mexiletine on cortical and axonal hyperexcitability in sporadic amyotrophic lateral sclerosis (ALS) in a phase 2 double‐blind randomized controlled trial. Methods Twenty ALS subjects were randomized to placebo and mexiletine 300 or 600 mg daily for 4 wk and assessed by transcranial magnetic stimulation and axonal excitability studies. The primary endpoint was change in resting motor threshold (RMT). Results RMT was unchanged with 4 wk of mexiletine (combined active therapies) as compared to placebo, which showed a significant increase (P = .039). Reductions of motor evoked potential (MEP) amplitude (P = .013) and accommodation half‐time (P = .002), secondary outcome measures of cortical and axonal excitability, respectively, were also evident at 4 wk on mexiletine. Conclusions The relative stabilization of RMT in the treated subjects was unexpected and could be attributed to unaccounted sources of error or chance. However, a possible alternative cause is neuromodulation preventing an increase. The change in MEP amplitude and accommodation half‐time supports the reduction of cortical and axonal hyperexcitability with mexiletine.

The c.*15C>T mutation in the GJB1 3' UTR segregates with CMTX1 in 8 generations. Penetrance in males and females is essentially complete. A straightforward genetic method to detect this mutation is described. Muscle Nerve 57: 859-862, 2018.

Objective: To evaluate how DSPN differs across the randomized DPP treatment groups and is associated with diabetes (DM) status, DM duration, and cumulative glycemic exposure. Methods: In the DPP, adults ≥25 years of age at high risk for DM (n=3234) were randomized to determine the effects of intensive lifestyle modification (ILS) or metformin (MET) compared to placebo (PLA) on incident diabetes. After DPP ended, participants were invited to join the DPPOS during which metformin was continued in those randomized to receive it. DSPN was rigorously assessed in 1,792 participants at DPPOS year 17 based on both symptoms and signs (pinprick, vibration, and monofilament). Multivariable logistic regression models were used to determine whether DSPN was associated with randomized treatment group, DM status and duration, and cumulative glycemic exposure. Results: At 21 years following DPP randomization, 66% had developed DM with median duration of 15 years. The prevalence of DSPN did not differ by DPP treatment group (21.5%, 21.5% and 21.9% in ILS, MET and PLA, respectively), but was slightly lower for those at risk for DM (19.6%) vs. those with DM (22.7%). There was a significant effect modification by age of the association between DPP treatment group and DSPN (p<0.05): the odds ratio (OR) for DSPN with ILS vs PLA decreased by 3.7% (95% CI 0.6-6.7) with each 1 year increase in age. MET vs. PLA was not associated with DSPN and age did not influence the null association. In models adjusted for treatment group, demographics, cardiometabolic risks, and low vitamin B12 or B12 supplement use, DSPN was associated with DM status (OR 1.40, p<0.001 vs. no DM), greater DM duration (OR 1.04 per 1 year, p<0.001), and higher time-weighted HbA1c (OR 1.85 per 1% increase, p<0.001). Conclusions: The likelihood of DSPN was higher for those with DM, longer DM duration, and higher cumulative glycemic exposure. Although ILS did not prevent DSPN overall, there were ILS benefits with increasing age. Disclosure C.Lee: Employee; Pfizer Inc. N.White: None. W.H.Herman: Advisory Panel; National Committee for Quality Assurance, Consultant; Merck Sharp & Dohme Corp., Other Relationship; National Institutes of Health, American Diabetes Association. D.Research group: None. A.Ciarleglio: None. S.Edelstein: None. J.P.Crandall: Research Support; Abbott Diabetes. D.Dabelea: None. R.B.Goldberg: None. S.E.Kahn: Advisory Panel; Anji Pharmaceuticals, Bayer Inc., Boehringer Ingelheim Inc., Eli Lilly and Company, Merck & Co., Inc., Other Relationship; Novo Nordisk. W.C.Knowler: None. M.Ma: None. Funding National Institute of Diabetes and Digestive and Kidney Diseases (UDK048489, UDK048339, UDK048377, UDK048349, UDK048381, UDK048468, UDK048434, UDK048485, UDK048375, UDK048514, UDK048437, UDK048413, UDK048411, UDK048406, UDK048380, UDK048397, UDK048412, UDK048404, UDK048387, UDK048407, UDK048443, UDK048400)