G.P.58 Muscle MRI in a filaminopathy family: Involvement of paraspinals is earlier and more severe than of thigh muscles

Mild to severe weakness of proximal and distal limb muscles is common in all types of myofibrillar myopathies (MFM). In clinical practice, it is important to know the specific distribution patterns of muscle involvement in order to differentiate the various subtypes. Muscle MRI is a useful tool to show the distribution and severity of muscle involvement in different muscle diseases. Here we report two patients with p.W2710X in FLNC gene mutation from a Macedonian family with 18 affected members. The patients were a male at 55 and a female at 51 years of age with 14 and 8years of disease duration, respectively. The onset symptom in both patients was difficulty in holding the waist up upon rising from a chair or climbing stairs. Muscle strength evaluation revealed that the most severely affected muscles were the lower extremity proximal and the trunk muscles in each patient without a significant difference in weakness distribution pattern. Muscle MRI scans for thigh, pelvic and lower paraspinal muscles were performed. Regardless of the duration of the disease the most severely affected muscles were the paraspinals, practically almost totally replaced by fat in both patients. Although to a slightly lesser degree, another relatively severely affected group was the posterior thigh muscles. Involvement in this latter group and in even the less affected gluteus maximus showed correlation with the disease duration. Anterior thigh compartment muscles seemed to remain relatively spared. Filaminopathy has not been listed among the myopathies that predominantly involve the trunk muscles. Although more reports are needed, our experience in two patients suggests that the inclusion of the lower paraspinal region in muscle MRIs in the work-up of MFMs may be a useful tool to differentiate filaminopathies from the other MFM subgroups.