In contrast, the expression of a second set of genes related to inflammatory processes and degeneration (Gfap for gliosis, H2Q7/8/9 for major histocompatibility complex type Ib, Arg1 for M1 microglial activation and Bax for the promotion of apoptosis) was not different between the genotypes in the striatum, the area that is the most sensitive to mHtt expression (Fig. 1M); the exception was Bcl2, which can antagonize the function of Bax25 but which role in HD is still under debate26. This evidence concerns the gene ARG1 and Huntington disease.