DAO and amyotrophic lateral sclerosis: Reduced enzyme activity has also been reported in spinal cord from an ALS case harboring this mutation (Mitchell et al., 2010), Additional studies on the human DAOG183R mutation that corresponds to the G181R substitution found in a strain of ddY mice lacking DAO activity also alters protein conformation and negatively affects the ability of the apoprotein to bind to the flavin cofactor in the orientation required for hydride-transfer during catalysis.