To assess the potential of Rho kinase genes as potential peripheral markers for HD in human or as pharmacodynamics markers to enable developing treatments targeting the Rho kinase pathway, we used quantitative real-time PCR of RhoA, ROCK1, PRK2, Profilin1, cofilin1, MYPT1, and LIMK1 to examine the pathway in more detail in leukocytes from HD patients as well as in human postmortem and R6/2 transgenic mouse brain tissue. The gene discussed is ROCK1; the disease is Huntington disease.