The authors hypothesise that Spt4, a transcription factor recently discovered to mediate transcription of long repeat sequences in HD, could be involved in transcription of the pathological hexanucleotide repeat expansion in C9orf72. The study generated three models with the pathological expansion (yeast, C. elegans and Drosophila) and found that deleting or knocking down Spt4 reduced or eradicated RNA foci aggregation and DPR production. The gene discussed is SUPT4H1; the disease is Huntington disease.