ACTR2 and Huntington disease: The alteration of mRNA levels of constituents of the Arp2/3 complex and actin-related proteins further substantiates the identification of CDC42 as an important hub gene in the brain since CDC42 can activate the Arp2/3 complex through Wiskott-Aldrich syndrome proteins [42] such as WAS, WASF1, WASF2, WASF3, and WASL that appeared to be neither robustly altered in the brain nor the blood of HD patients.