• MYOPATHY

In their JNNP paper Uruha et al1 explore the diagnostic utility of necklace cytoplasmic bodies in patients with hereditary myopathy with early respiratory failure (HMERF). HMERF is a rare autosomal dominant disease characterised by skeletal muscle weakness and respiratory failure as early symptoms, usually presenting in the third or fourth decade of life. The muscle pathology is characterised by the presence of multiple cytoplasmic bodies, other protein aggregates, myofibrillar disarray and degradation. To date, all patients presenting with HMERF harbour mutation of exon 343 of titin (TTN), encoding the fibronectin III 119 subdomain (FN3 119).2–5 Most recently, it has been shown that HMERF substitutions impair the solubility of the FN3 119 domain, suggesting protein misfolding as a potential mechanism of disease.6

There is currently debate as to whether coinheritance of a variant within the tyrosine kinase domain can alter the severity associated with a FN3 119 mutation …