Overview Clinical Study of the Effect of Vitamin D on the RAAS System in Children With Chronic Orthostatic Intolerance (POTS) Status: Recruiting Trial end date: 2021-12-20 Target enrollment: Participant gender: Summary chronic orthostatic intolerance in children;postural tachycardia syndrome;vitamin D;RAAS;atecholamines Phase: Early Phase 1 Details Lead Sponsor: KongyujieCollaborator: LanZhou UniversityTreatments: ErgocalciferolsVitamin DVitamins