FGF9 and Huntington disease: It has been shown that exogenous FGF-9 may promote neuronal development and synaptic growth in striatal cell models of HD in response to anti-oxidant and anti-apoptotic effects via extracellular signaling that modulates the ERK/NF-κB pathway (Yusuf et al., 2019, 2021a,b), which provides a novel insight into the treatment of cognitive decline due to HD.