Preprint: KLHL40 gene replacement improves survival and muscle function in a severe nemaline myopathy mouse model

Nemaline myopathy is a group of inherited skeletal muscle disorders characterised by profound muscle weakness and, in the most severe forms, perinatal lethality. No disease-modifying therapies currently exist. Recessive loss-of-function mutations in KLHL40, which encodes a muscle-specific protein that stabilises sarcomeric components, cause a particularly severe subtype. A preprint posted to bioRxiv describes preclinical work using adeno-associated virus (AAV)-mediated gene replacement to restore KLHL40 expression in a mouse model of this condition.

The researchers report that KLHL40 gene replacement therapy improved survival and skeletal muscle function relative to untreated animals. Given that KLHL40 deficiency results from loss of a structural or stability protein rather than a gain-of-function mechanism, gene replacement — providing a working copy of the gene — is a conceptually straightforward therapeutic approach, though translating such strategies to human patients involves numerous additional steps.

The preprint has not yet undergone peer review. The study sits within a broader wave of preclinical gene therapy programmes targeting rare inherited muscle disorders, several of which have now reached clinical trials for related conditions.

This finding is of primary interest to researchers in neuromuscular genetics, gene therapy, and skeletal muscle biology, and to educators and students covering inherited myopathies.