G.P.161 - Muscle MRI in sarcoglycanopathies

Abstract

Sarcoglycanopathies (LGMD2C–2F) are limb-girdle muscular dystrophies caused by mutations in one of the four genes encoding for muscle sarcoglycans. The objective of this study is to characterize the pattern and spectrum of MRI involvement in a large cohort of patients with sarcoglycanopathy. Lower limb MRI scans of LGMD2C–2F patients were collected in multiple neuromuscular referral centers in Europe and the USA, ranging from severe childhood variants to milder adult onset forms. Muscle involvement was evaluated semiquantitatively on T1-weighted images according to a visual score, and the global pattern was assessed as well. As a result, a common pattern of involvement was found in all the sarcoglycanopathies irrespective of the mutated gene. The most and earliest affected muscles were the adductors, glutei and posterior thigh groups, while lower leg muscles were relatively spared even in advanced disease. Muscle involvement on MRI is consistent in LGMD2C–F patients and some clues can be helpful in distinguishing sarcoglycanopathies from other LGMDs or dystrophinopathies, which represent the most common differential diagnoses. Muscle MRI can also provide insights about progressive involvement of the different muscles over time as well as about selective susceptibility or resistance of specific muscles when one of the sarcoglycans is deficient.