Two adjacent samples of 2.0 cm3 from the belly of each deltoid, quadriceps femoris, and the gastrocnemius muscles bilaterally for a total of 12 muscle samples are dissected. The choice of muscles was based on several considerations, including the likelihood that dysfunction would contribute to motor impairment, the availability of clinical measures of their function, and that the site of biopsy would not leave a visible scar which would preclude an open casket and wake following the procedure. Two 1.0 cm portions of muscle are oriented on cork in cross-section, placed in OCT, and snap frozen in liquid nitrogen insulated by isopentane. Frozen muscle is stored (in vials containing frozen water for hydration) at −80°C. The remainder of the muscle is fixed in 4% paraformaldehyde for 2–3 days and embedded in paraffin.
