A. Representative images of semithin section analysis of sciatic nerves from Mtmr2-/- and Mtmr2-/-;Nrg1 (III)+/- mice at 6 months. Myelin outfoldings (arrowheads) are reduced in Mtmr2-/-;Nrg1 (III)+/- nerves (n=9) as compared to Mtmr2-/- (n=8), results are mean ± SEM, p=0.0037, two-tailed Mann Whitney U test.B. G-ratio analysis on sciatic nerves from Mtmr2-/-, Mtmr2-/-;Nrg1 (III)+/-, and Nrg1 (III)+/- mice at 6 months indicates that myelin thickness of Mtmr2-/-;Nrg1 (III)+/- is similar to Nrg1 (III)+/- nerves and different from Mtmr2-/-, which is in the normal range as already reported (Bonneick et al, 2005), n=5 animals per genotype.Mean g-ratios: Mtmr2-/- 0.67 ± 0.03, 2129 fibers, n=5 animals; Mtmr2-/-;Nrg1 (III)+/- 0.71 ± 0.03, 2139 fibers, n=5 animals; Nrg1 (III)+/- 0.72 ± 0.03, 2152 fibers, n=4 animals. Mtmr2-/- as compared to Mtmr2-/-;Nrg1 (III)+/-, p=0.0145; Mtmr2-/- as compared to Nrg1 (III)+/-, p=0.0030, and Mtmr2-/-;Nrg1 (III)+/- as compared to Nrg1 (III)+/- p=0.3193, repeated measures ANOVA. 