Moreover, histone deacetylase (HDAC) modulates the expression of the polycystic kidney disease-1 gene (Pkd1). HDAC inhibitors can reduce cyst formation in Pkd1-deficient mice (Van Bodegom et al., 2006) and delay the impairment of renal function in Pkd2-deficient mice (Xia et al., 2010). The gene discussed is HDAC9; the disease is cyst.