Whole-Body Muscle Computed Tomography Study of Desminopathy-A Case Series.

INTRODUCTION/AIMS: Desminopathy is a myofibrillar myopathy caused by pathogenic variants in DES and characterized by heterogeneous clinical and imaging manifestations. Although preferential muscle involvement has been described, systematic whole-body computed tomography (CT) analyses remain limited. This study aimed to characterize patterns of skeletal muscle involvement and imaging-defined severity in desminopathy using whole-body CT.

METHODS

Whole-body CT scans from 14 adults with DES-related myopathy were evaluated using a modified Mercuri score across 43 muscles. Multivariate analyses were applied to characterize patterns of muscle involvement, define imaging-based severity groups, and assess variable associations.

RESULTS

Fourteen adult patients (11 males, 3 females; age range 29-69 years) with symptom duration ranging from 2 to 29 years were included. Early involvement was observed across thigh musculature, with semitendinosus consistently affected. Extensor digitorum longus, fibularis brevis, and tibialis posterior demonstrated discriminatory utility across severity groups. Increasing severity was associated with broader involvement of thigh, gluteal, trunk, and lower-leg muscles. Variant location showed domain-associated tendencies, with Coil 2B variants associated with prominent vastus involvement and trunk-directed patterns, whereas tail-domain variants were associated with greater posterior thigh and trunk involvement. Side-to-side asymmetry occurred variably and was most consistently observed in tibialis anterior.

DISCUSSION: Whole-body CT imaging delineates coordinated, severity-dependent patterns of muscle involvement in desminopathy. Our work illustrates the value of whole-body CT for characterizing global patterns of muscle involvement and for informing future imaging-based studies in desminopathy, including larger cohorts and longitudinal investigations to better define disease progression and imaging biomarkers.