In an additional study, they found that Arg1 (an anti-inflammatory gene that codes for arginase1, an arginine utilization enzyme) was expressed in the parts of the animal brain with high levels of amyloidosis prior to the onset of neuronal degeneration and cell death, an indication that chronic brain arginine deprivation could be the cause of neuronal cell death in AD, and the subsequent cascade of AD pathology. The gene discussed is ARG1; the disease is Alzheimer disease.