AGT and hereditary spastic paraplegia: Angiotensinogen (AGT) is involved in the production of angiotensin II which is the main mediator of action of the rennin-angiotensin system (RAS) [11] whereas the RAS mediates the regulation of sodium homeostasis, blood pressure, and inflammation [12], so it was speculated that AGT gene polymorphism might be the key biomarker predicting the risk of HSP/HSPN through its influence on the level of AGT [13].