PNKD (PNKD Serine/Threonine Kinase): PNKD is a gene that encodes a serine/threonine kinase, an enzyme involved in phosphorylation reactions. This gene plays a crucial role in regulating neuronal activity and movement control. Mutations in PNKD have been associated with paroxysmal nonkinesigenic dyskinesia, a neurological disorder characterised by sudden and involuntary movements.