Fig. 1.

Focal depletion of mitochondria in skeletal muscles of a human R350P desminopathy patient and R349P desmin knock-in mice. a Cytochrome C oxidase (COX, brown) and succinate dehydrogenase (SDH, blue) double-stains of transverse and longitudinal cryosections from a German patient harboring the heterozygous R350P (c.1049G>C) desmin missense mutation [3]. Note the multiple rubbed-out areas (asterisks) devoid of COX and SDH enzyme activities demonstrating the absence of mitochondria. The right image represents a false color representation of two superimposed serial cryosections stained for COX (magenta) and desmin (black). Sarcoplasmic desmin-positive protein aggregates clearly display a distribution which is independent from the mitochondrial lesion pathology. b, c COX (b) and SDH (c) stains of transverse and longitudinal cryosections from 3-month-old R349P (c.1045_1047delAGG>insCCC) desmin knock-in mice. Fibers of homozygote (HOM) animals display large and small areas of diminished enzyme stains (asterisks). Furthermore, muscle fibers in homozygote animals show an abnormal, thread-like distribution of mitochondria. Heterozygous (HET) mice showed no overt pathology as compared to wild-type (WT) littermates