TF and periodic limb movement disorder: CSF, cerebrospinal fluid; RLS, restless legs syndrome; IRLSSG, International Restless Legs Syndrome Study Group; PSG, polysomnography; FCM, ferric carboxymaltose; TSAT, transferrin saturation; ICSD-3, International Classification of Sleep Disorders, 3rd edn.; PLMD, periodic limb movement disorder; IV, intravenous; LMWID, low-molecular-weight iron dextran; HMWID, high-molecular-weight iron dextran; IDA, iron deficiency anemia