LAUSR

BACKGROUND DYT-VPS16 is a rare monogenic form of dystonia caused by pathogenic variants in the vacuolar protein sorting 16 homolog (VPS16) gene. Although increasingly recognized, the clinical spectrum and therapeutic responsiveness, particularly to deep brain stimulation (DBS), remain incompletely defined. CASES We report six affected individuals (5 males, 1 female) from five unrelated Indian families harboring VPS16 variants. The median age at onset was 16.5 years (range, 8-18 years). Dystonia began in the cervical (n = 2), upper limb (n = 2), or laryngeal (n= 2) regions. Additional features included tremor (n = 2) and sleep disturbances (n = 1). LITERATURE REVIEW A structured literature review identified 34 previously reported DYT-VPS16 cases treated with DBS. Pooled analysis revealed a responder rate (defined as ≥30% improvement in BFMDRS-M) of 0.57 (95% CI: 0.31-0.81; I2 = 22.9%) suggesting a favorable therapeutic response in this subgroup. CONCLUSION Our findings broaden the genotypic and phenotypic landscape of DYT-VPS16, suggesting a more motor-predominant and potentially milder expression in South Asian patients. DBS appears to confer meaningful clinical benefit in selected cases, highlighting the importance of early genetic diagnosis in guiding treatment.