Novel muscle MRI features in Desmin related myasthenic myopathy

Primary desminopathies often present as myofibrillar myopathy with predominant dominant inheritance. There are only few reports of recessive desminopathies. Distinct muscle MRI features with predominant involvement of gluteus maximus, semitendinosus, sartorius, gracilis and peroneal muscles have been described in dominant desminopathies. We report five patients with recessive desminopathies carrying novel homozygous DES variants (c.1023+5G>A and c.958delG). All presented with features of congenital myasthenic syndrome since early childhood. Novel MRI features with fatty infiltration of gluteus medius/ minimus, adductor magnus, quadriceps femoris and hamstrings were noted. Gracilis and short head of biceps femoris were consistently spared. In the leg, in addition to peroneal muscle involvement, there was severe fatty atrophy of anterior leg muscles. There was also myoedema posterior leg compartment. Thus, this study expands the imaging features of desminopathies with myasthenic syndrome.