Selective muscle involvement in a 59-year-old man (A, B, E, F) and his 28-year-old daughter with centronuclear myopathy (C, D, G, H) due to a mutation in the dynamin 2 (DNM2) gene, muscle MRI, transverse, T1-weighted sections from the proximal (A, C) and distal (B, D) thigh and the proximal (E, G) and distal lower leg (F, H). In the thigh there is increased signal intensity within the adductor longus (AL), semimembranosus (SM), rectus femoris (RF), biceps femoris (BF), and vastus intermedius (VI) muscles with relative sparing of the adductor magnus (AM), gracilis (G), sartorius (S), semitendinosus (ST), vastus lateralis (VL), and vastus medialis (VM) muscles. Within the lower leg, there is predominant involvement of the gastrocnemius (GA), soleus (SO) an tibialis anterior (TA) muscles with relative sparing of the peroneal group (PG). Muscle involvement, particularly within the thigh, is milder in the daughter compared to her father. The pattern is distinct from that reported in congenital myopathies associated with mutations in the skeletal muscle ryanodine (RYR1) gene. (Figure courtesy of Dr Carsten Boennemann and Dr Joachim Schessl, reproduced from Schessl et al., Neuromuscular Disorders 2007; 17:28–32, with permission from Elsevier).