Muscle magnetic resonance imaging involvement patterns in nemaline myopathies

Abstract Objective Characterise the diagnostic and prognostic value of muscle MRI patterns as biomarkers in a genetically heterogeneous nemaline myopathy (NM) patient cohort. Methods Modified Mercuri scoring of lower limb MRI in genetically characterised NM patients referred to the highly specialised service for congenital myopathies at Great Ormond Street Hospital. Findings were compared to clinical data and MRI patterns derived from collated published data. Results Twenty‐seven patients with MRI were identified (8 NEB‐NM, 13 ACTA1‐NM, 6 TPM3‐NM). NEB‐NM demonstrated sparing of the thigh. ACTA1‐NM demonstrated diffuse thigh involvement, notable in the vasti, sartorius and biceps‐femoris, with relative adductor and gracilis sparing. TPM3‐NM demonstrated diffuse thigh involvement notable in biceps‐femoris and adductor magnus with relative rectus femoris, adductor longus and gracilis sparing. In the lower leg, the soleus and tibialis anterior are notably involved in all three genotypes. NEB‐NM and ACTA1‐NM demonstrated relative gastrocnemii and tibialis posterior sparing, while TPM3‐NM showed significantly more tibialis posterior involvement (P =