Spastic Paraplegia 9a, Autosomal Dominant, also known as hereditary spastic paraplegia 9a, is related to spastic paraplegia 9b, autosomal recessive and spastic paraplegia type 5a, and has symptoms including upper motor neuron signs An important gene associated with Spastic Paraplegia 9a, Autosomal Dominant is ALDH18A1 (Aldehyde Dehydrogenase 18 Family Member A1). Affiliated tissues include eye and spinal cord, and related phenotypes are spastic gait and lower limb hyperreflexia