HPDL and hereditary spastic paraplegia: Our study investigates the role of 4-hydroxyphenylpyruvate dioxygenase-like (HPDL) protein in cortical neurogenesis and mitochondrial activity, since mutations in the HPDL gene are associated with a childhood-onset form of hereditary spastic paraplegia characterized by corticospinal tract degeneration and cortical abnormalities.