SPG7 (Spastic Paraplegia 7, Paraplegin): SPG7 is a mitochondrial protein involved in the maintenance and function of mitochondria, especially in ATPase assembly. It plays a key role in neural and mitochondrial health. Mutations in SPG7 are a common cause of hereditary spastic paraplegia, a neurodegenerative disorder marked by progressive stiffness and weakness in the lower limbs.