Distinct muscle imaging patterns in myofibrillar myopathies

Abstract

Objective To compare muscle imaging findings in different subtypes of myofibrillar myopathies (MFM) in order to identify characteristic patterns of muscle alterations that may be helpful to separate these genetic heterogeneous muscular disorders. Methods Muscle imaging and clinical findings of 46 patients with MFM were evaluated (19 desminopathy, 12 myotilinopathy, 11 filaminopathy, 1 αB-crystallinopathy, and 3 ZASPopathy). The data were collected retrospectively in 43 patients and prospectively in 3 patients. Results In patients with desminopathy, the semitendinosus was at least equally affected as the biceps femoris, and the peroneal muscles were never less involved than the tibialis anterior (sensitivity of these imaging criteria to detect desminopathy in our cohort 100%, specificity 95%). In most of the patients with myotilinopathy, the adductor magnus showed more alterations than the gracilis muscle, and the sartorius was at least equally affected as the semitendinosus (sensitivity 90%, specificity 93%). In filaminopathy, the biceps femoris and semitendinosus were at least equally affected as the sartorius muscle, and the medial gastrocnemius was more affected than the lateral gastrocnemius. The semimembranosus mostly showed more alterations than the adductor magnus (sensitivity 88%, specificity 96%). Early adult onset and cardiac involvement was most often associated with desminopathy. In patients with filaminopathy, muscle weakness typically beginning in the 5th decade of life was mostly pronounced proximally, while late adult onset (>50 years) with distal weakness was more often present in myotilinopathy. Conclusions Muscle imaging in combination with clinical data may be helpful for separation of distinct myofibrillar myopathy subtypes and in scheduling of genetic analysis.

A Combined Laser Microdissection and Mass Spectrometry Approach Reveals New Disease Relevant Proteins Accumulating in Aggregates of Filaminopathy Patients

“…Filaminopathy is leading to a progressive muscle weakness usually manifesting between the fourth and sixth decade of life. The pattern of severely and hardly affected muscles detected by magnetic resonance imaging is very homogeneous across patients with different FLNC mutations (8,9, and unpublished data). In advanced stages of the disease, patients generally lose the ability to walk and show respiratory insufficiency because of weakness of respiratory muscles.…”

Tragedy in a heartbeat: malfunctioning desmin causes skeletal and cardiac muscle disease

“…In the thigh, the earliest and always most severely affected muscle is the semitendinosus (a muscle at the back of the thigh), followed by the sartorius and gracilis. The effects on these muscles always exceeds the involvement of the adductor magnus, biceps femoris, and semimembranosus (71). The anterior compartment (the rectus femoris, vastus lateralis, intermedius, and medialis) is relatively spared.…”

“…The gluteus maximus is more severely involved than gluteus medius and minimus. Generally, the severity of degeneration in distal muscles always exceeds that of proximal muscles (71).…”

“…Muscle imaging studies performed in patients with desminopathy have identified a recognizable pattern of muscle involvement (71). In the lower leg, the peroneal muscles display substantially more myopathic changes than either the tibialis anterior or the muscles of the posterior compartment (the soleus and the medial and lateral gastrocnemius).…”

Muscle MRI findings in a one-year-old girl with merosin-deficient congenital muscular dystrophy type 1A due to LAMA2 mutation: A case report

“…Fatty infiltration of muscles was assessed by the Mercuri scale, as modified by Fischer et al (2) (Fig. 1).…”