As in other genetic diseases (Holbrook et al, 2004; Rio Frio et al, 2008), the low levels of Coq9 mRNA are due to NMD because the incubation of Coq9Q95X and Coq9R239X MEFs with the NMD inhibitor cyclohexamide increased the Coq9 mRNA levels. The gene discussed is COQ9; the disease is hereditary disease.