Update: Candidate biomarkers and modifiers of disease progression

Posted by Friends of FSH Research on Jun 4, 2026

DUX4 expression in skeletal muscle causes FSHD. DUX4 is a transcription factor that induces the expression of many genes that alter the function of the muscle cell. DUX4 also induces the expression of many endogenous retroviruses, most of which are non-functional remnants of viruses that have accumulated in our genome during the course of evolution. We have recently determined that some of the DUX4-induced retroviruses might be capable of generating viral-like particles. These can be secreted from the DUX4 expressing muscle cell and it is possible that they can infect adjacent muscle cells or possibly be detected in the circulation. This study will better characterize the components of these viral-like particles, their ability to infect adjacent cells and contribute to disease progression, and their utility as circulating biomarkers in FSHD. Initial studies in tissue culture show that DUX4-expressing cells and FSHD myotubes, but not control myotubes, release particles that contain viral-like proteins and RNA in a complex consistent with a viral-like particle. Ongoing work suggests that some of these RNAs are transferred to other cells, however, it remains to be shown whether the RNAs enter the cells in a way that allows translation to form new proteins.