These novel ideas for future therapeutic targeting for patients having SPG4 due to haploinsufficient mutations in SPAST, and potentially for other neurodegenerative diseases such as MS with downregulation of spastin function, can be tested in animal models [59], [64], [68], [73], [83]–[84] and if and when warranted subsequently in clinical trials. The gene discussed is SPAST; the disease is myeloid sarcoma.