A naïve human spleen scFv phage-display library screened against the N-terminal 17 amino acids of htt generated the scFv-C4 intrabody, which successfully counteracts in situ length-dependent htt aggregation, in both cell culture [18], [19], [20], [21] and Drosophila models of HD [22]. This evidence concerns the gene C4A and Huntington disease.