Besides, mRNA levels of several constituents of the Arp2/Arp3 complex (ACTR2/Arp2: blood; ACTR3/Arp3: blood and brain; ACTR3B: brain; ARPC5: blood; ACTR6: brain), that interacts with the HIP1R-cortactin complex and is activated by CDC42, were altered in HD patients. The gene discussed is ACTR2; the disease is Huntington disease.