Objective:To investigate the reasons for efficacy heterogeneity analysis of 3 patients with pantothenate kinase associated neurodegeneration (PKAN) from one family after deep brain stimulation (DBS).Methods:Three PKAN patients with the same PANK2 gene mutation from one family, admitted to and accepted bilateral subthalamic nucleus (STN)-DBS in our hospital from May to August 2021, were selected. The clinical manifestations, including general condition, medical history, symptoms, and signs, of these 3 patients were collected; Burkefahn-Marsden Dystonia Movement Rating Scale (BFMDRS) scores and surface electromyography results were analyzed and compared before DBS and 2 weeks and 6 months after DBS. Results:The clinical phenotype of these 3 patients had obvious heterogeneity: patient 1 had the latest onset age and shortest duration, and the main manifestation included abnormal body activity and forced postures, without obvious body deformation; preoperative surface electromyography suggested that the involuntary muscle contractions intensity was the smallest, and involuntary movements characterized by alternating patterns of contractile discharge activity were the predominant. The patient 2 and patient 3 had early onset age and long course of disease with gradually aggravated disease, and manifested as lower limb claudication and involuntary limb torsion; patient 3 also had marked limb deformities; preoperative surface electromyography showed high intensity of involuntary muscle contraction and torsional spastic dystonia characterized by co-contractile firing activity. The BFMDRS scores and surface electromyography results of the 3 patients after DBS were significantly improved as compared with those before surgery, with obvious heterogeneity; the improvement rates of BFMDRS scores of patient 1, 2 and 3 were 88.1%, 60.5%, and 43.2%, and the improvement rates of surface electromyography were 82.36%, 63.79% and 72.25%, respectively,at 6 months after surgery as compared with those before surgery.Conclusion:PKAN exhibits complicated clinical heterogeneity, which is one of the reasons for efficacy heterogeneity for PKAN after DBS.