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Background and purpose: BSCL2 heterozygote mutations are a common cause of distal hereditary motor neuropathies (dHMNs). A series of BSCL2 patients is presented and clinical, neurophysiological and muscle magnetic resonance imaging (MRI) findings are correlated. Methods: Twenty‐six patients from five families carrying the p.N88S mutation were identified. Age of onset, clinical phenotype (dHMN, Charcot–Marie–Tooth, spastic paraplegia), physical examination, disability measured as a modified Rankin Scale score and neurophysiological findings were collected. A whole body muscle MRI had been performed in 18 patients. The pattern of muscle involvement on T1‐weighted and short time inversion recovery sequences was analysed. Hierarchical analysis using heatmaps and an MRI Composite Score were generated. Statistical analysis was carried out with STATA SE v.15 (TX, USA). Results: The mean age was 51.54 ± 19.94 years and 14 patients were men. dHMN was the most common phenotype (50%) and five patients (19.23%) showed no findings on examination. Disease onset was commonly in childhood and disability was low (modified Rankin Scale score 1.34 ± 1.13) although median time since onset of disease was 32 years (range 10–47). Charcot–Marie–Tooth‐like patients were more disabled and disability correlated with age. On muscle MRI, thenar eminence, soleus and tibialis anterior were most frequently involved, irrespective of clinical phenotype. MRI Composite Score was strongly correlated with disability. Conclusion: Patients with the p.N88S BSCL2 gene mutation are phenotypically variable, although dHMN is most frequent and generally slowly progressive. Muscle MRI pattern is consistent regardless of phenotype and correlates with disease severity, probably serving as a reliable outcome measure for future clinical trials. [ABSTRACT FROM AUTHOR]

Emery–Dreifuss muscular dystrophy (EDMD) is characterized by contractures involving ankles, elbows and spine and scapuloperoneal weakness. Mutations in two genes, emerin and lamin A/C cause the disease in the majority of cases. Clinical data are not helpful to differentiate between both genotypes. We hypothesized that muscle imaging techniques could be useful to differentiate phenotypes to guide the genetic studies. We included patients with mutations in emerin or lamin A/C genes from 5 different centres. Patients were classified in 4 different phenotypes: EDMD, limb girdle muscle weakness (LGMD), cardiomyopathy and pre-symptomatic patients. Muscle images from trunk, thighs and legs were obtained. Muscle atrophy was quantified using Mercuri’s scale. We used Wilcoxon test to compare muscle involvement between both genotypes. Differences were considered significant if p < 0.05. We included 42 patients (17 females) of which 10 had mutations in emerin gene and 32 in lamin A/C gene. 19 patients had EDMD phenotype (10 emerin patients and 9 lamin A/C), 12 had LGMD, 6 had isolated cardiomyopathy and 5 were pre-symptomatic. Muscle MRI was performed in 19 patients and CT scan in 23 patients. We found a common pattern of involvement in all patients with EDMD or LGMD characterized by atrophy of paravertebral muscles, glutei muscles, vastus intermedius, lateralis and medialis, long head of biceps, semimebranosus, soleus and gastrocnemius medialis and lateralis. We found significant differences in the degree of involvement of semitendinosus and peroneus that were more commonly and more severely atrophic in patients with mutations in emerin gene compared to patients with mutations in lamin A/C. We observed a common pattern of muscle involvement in MRI/CT scans of patients with mutations in the emerin and lamin A/C gene. However, severe atrophy of peroneus and semitendinosus muscles was only observed in patients. [ABSTRACT FROM AUTHOR]