Single section Western blot (SSWB) is an improved methodology for molecular diagnosis of the muscular dystrophies, requiring only a single 8-microm muscle biopsy cryosection for the simultaneous analysis of multiple disease candidates. The authors demonstrate that SSWB can be used for diagnosis of dystrophinopathies, to identify haploinsufficiency in autosomal dominant laminopathy, and as a tool to distinguish between primary and secondary immunohistochemical abnormalities in limb-girdle muscular dystrophy type 2B.