(A) Forelimb grip strength measurements for 1-year-old littermate control (C57) and DNAJB6-F90I heterozygous mice and (B) inverted wire screen holding for the same animals as in A. *P < 0.05 and **P < 0.005, by paired Student’s t test for comparisons between groups. (C and D) Immunoblot of lysates from TA and GAST muscles from 3 different 1-year-old C57 and F90I heterozygous mice using antibodies against DNAJB6, HSP70, desmin, and GAPDH. Quantitation of 3 replicates for each blot is shown in Supplemental Figure 2, B and C. (E) qPCR analysis of TA muscle from five 1-year-old F90I heterozygotic and C57 mice. Data are presented as the fold change versus C57 controls. *P = 0.05–0.01, by Student’s t test; P = 0.0023, Bonferonni-adjusted value for multiple comparisons.