European muscle MRI study in limb girdle muscular dystrophy type R1/2A (LGMDR1/LGMD2A)

Andrea Barp, Pascal Laforet, Luca Bello, Giorgio Tasca, John Vissing, Mauro Monforte, Enzo Ricci, Ariane Choumert, Tanya Stojkovic, Edoardo Malfatti, Elena Pegoraro, Claudio Semplicini, Roberto Stramare, Olivier Scheidegger, Jana Haberlova, Volker Straub, Chiara Marini-Bettolo, Nicoline Løkken, Jordi Diaz-Manera, Jon A UrtizbereaEugenio Mercuri, Martin Kynčl, Maggie C Walter, Robert Y Carlier

46 Citations (Scopus)

Abstract

BACKGROUND: Limb girdle muscular dystrophy type R1/2A (LGMDR1/LGMD2A) is a progressive myopathy caused by deficiency of calpain 3, a calcium-dependent cysteine protease of skeletal muscle, and it represents the most frequent type of LGMD worldwide. In the last few years, muscle magnetic resonance imaging (MRI) has been proposed as a tool for identifying patterns of muscular involvement in genetic disorders and as a biomarker of disease progression in muscle diseases. In this study, 57 molecularly confirmed LGMDR1 patients from a European cohort (age range 7-78 years) underwent muscle MRI and a global evaluation of functional status (Gardner-Medwin and Walton score and ability to raise the arms).

RESULTS: We confirmed a specific pattern of fatty substitution involving predominantly the hip adductors and hamstrings in lower limbs. Spine extensors were more severely affected than spine rotators, in agreement with higher incidence of lordosis than scoliosis in LGMDR1. Hierarchical clustering of lower limb MRI scores showed that involvement of anterior thigh muscles discriminates between classes of disease progression. Severity of muscle fatty substitution was significantly correlated with CAPN3 mutations: in particular, patients with no or one "null" alleles showed a milder involvement, compared to patients with two null alleles (i.e., predicting absence of calpain-3 protein). Expectedly, fat infiltration scores strongly correlated with functional measures. The "pseudocollagen" sign (central areas of sparing in some muscle) was associated with longer and more severe disease course.

CONCLUSIONS: We conclude that skeletal muscle MRI represents a useful tool in the diagnostic workup and clinical management of LGMDR1.

Original languageEnglish
JournalJournal of Neurology
Volume267
Issue number1
Pages (from-to)45-56
Number of pages12
ISSN0340-5354
DOIs
Publication statusPublished - Jan 2020

Keywords

  • CAPN3 mutations
  • LGMDR1/LGMD2A
  • Mercuri score
  • Muscle MRI

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