American researchers have identified, for the first time, a pathogenic variant of the CAP2 gene present in a heterozygous state in a sporadic form of nemaline myopathy. The child presented with neonatal onset hypotonia and, above all, very severe dilated cardiomyopathy:
- the CAP2 gene encodes a cyclase-binding protein (cyclase-associated-protein type 2),
- functional studies have confirmed the involvement of this new gene both in terms of the amount of protein and the mRNAs produced,
- a mouse model invalidated for this gene presented a muscular and cardiac phenotype similar to that of the child,
- his parents were healthy carriers of the variant and had no heart disease,
- the child underwent a heart transplant when he was one year old.
This gene enriches the already long list of genes involved in nemaline myopathies.