Based on an analysis of images obtained from full body magnetic resonance imaging (MRI) of 27 patients with LAMA2-related congenital muscular dystrophy (CMD), aged 2 to 62 years, 6 of whom had never acquired the ability to walk, an international collaboration coordinated by the team at the Raymond-Poincaré Hospital (Garches) has identified that:
- the replacement of muscle tissue by fatty tissue is predominant on the subscapularis muscles, the lombar paraspinal muscles, the gluteus minimus and medius muscles, the posterior compartment of the thigh muscles (adductor magnus, biceps femoris/hamstring muscles), both in ambulatory and non-ambulatory patients;
- the degree of fatty involution correlates with the duration of the disease, rather than with clinical severity or age at onset of the disease;
- certain adult patients present a “sandwich sign” image similar to that observed in collagen VI deficiency, but subscapularis and gluteus minimus/medius involvement allows the two diseases to be distinguished;
- involvement of the white matter always spares the corpus callosum, the internal capsule and the cerebellum; abnormalities in the development of the cerebral cortex were found in three patients (one non-ambulatory and two ambulatory), all of whom presented epilepsy and cognitive impairment.
The authors conclude that full body MRI is a good diagnostic tool that helps to detect brain and muscle abnormalities that are characteristic of LAMA2-related CMD and that images of the thigh muscles appear to be good markers of disease progression.
