Fig. 3.

Sequencing and muscle MRI in Patient WES9. a – variants in collagen VI genes identified by Sanger sequencing and WES in this patient. b – Pedigree. c – Visualisation of exome sequencing reads in patient DNA from blood with arrow indicating chr21:47,410,198 G > T (hg19) corresponding to COL6A1 c.957G > T; d – Sequencing chromatograms in patient DNA and parental DNA with COL6A1 c.957G > T variant indicated by arrows, height of sequencing peak in patient with DNA extracted from both blood and fibroblasts is lower than expected suggestive of mosaicism. Fibroblasts were obtained from skin biopsy taken from the right arm, which clinically is less severely affected than the left. e-i – T1 weighted axial MRI images of pelvis and lower limbs. In the pelvis (E) there is diffuse involvement of the gluteus maximus and medium with the left side more severely affected. In the thighs (F&G) there is sparing of gracilis and vastus medialis on the right, and diffuse involvement of all muscles on the left. There is central sparing of the vastus lateralis in the thighs and a ‘central shadow’ of increased signal intensity in the rectus femoris on the left (F&G) and less marked on the right, both of which are typical of COL6-RD [56]. In the calves there is peripheral involvement of the gastrocnemius and soleus on the left, with less pronounced peripheral involvement of the distal gastrocnemius on the right