The slow a-tropomyosin gene (TPM3) has been associated with three distinct histological entities: nemaline myopathy (NM, NEM1), congenital fibre-type disproportion (CFTD), and cap disease (CD). Here, the authors describe a patient presenting an early-onset congenital myopathy associated with a combination of well-separated cap structures and nemaline bodies in his muscle biopsy. Exome sequencing analysis allowed them to identify a de novo missense mutation in the TPM3 gene. This study confirms the extreme variability of morphological findings in TPM3-related myopathies, and proves that cap and nemaline bodies are two sides of the same ‘coin’.
