Upper body involvement in GNE myopathy assessed by muscle imaging

Abstract

Upper body muscle involvement has never been systematically investigated in GNE myopathy (GNEM). Aims of our study were to explore upper body involvement in GNEM patients by means of muscle MRI, to compare the degree of pathology with that of lower body and to validate the MRI pattern of the lower limbs in novel patients. MRI scans of 9 GNEM patients were retrospectively evaluated. T1-weighted and short-tau inversion recovery images were scored. As a result, serratus anterior was involved in all patients, followed by subscapularis and trapezius muscles. The majority of scans consistently showed hypotrophy of pectoralis minor. Conversely, cranial muscles including the tongue were always spared while pectoralis major and latissimus dorsi were relatively spared. We confirmed the known pattern of involvement in the pelvic girdle and limbs, that were more significantly affected than the upper girdle in all disease stages. Paraspinal muscles were also frequently affected displaying both a cranio-caudal and latero-medial gradient of severity along the body axis. Upper girdle MRI highlights a selective muscle involvement in GNEM, offering an added value in patients’ diagnostic workup and deep stratification.