BSCL2 encodes seipin, a protein essential for lipid droplet biogenesis and cellular energy metabolism. Seipin plays a crucial role in the formation and maturation of lipid droplets, which serve as storage organelles central to lipid and energy homeostasis 1. The protein localizes to endoplasmic reticulum-mitochondria contact sites (MAMs) where it regulates mitochondrial calcium import and metabolism 2. Seipin associates with calcium regulators including SERCA2, IP3R, and VDAC, and its removal leads to defective mitochondrial calcium influx, reduced Krebs cycle metabolites, and decreased ATP levels 2. Mutations in BSCL2 cause multiple distinct clinical phenotypes depending on the specific variant. Loss-of-function mutations typically result in congenital generalized lipodystrophy type 2 (Berardinelli-Seip syndrome), characterized by lipoatrophy, metabolic complications, and insulin resistance 3. Specific variants like c.985C>T cause Celia's encephalopathy, a progressive neurological disorder with poor prognosis due to aberrant seipin accumulation in neurons 4. Additional BSCL2 mutations are associated with hereditary spastic paraplegia type 17 and distal hereditary motor neuropathy, highlighting the protein's importance in neuronal function 56. The diverse clinical manifestations underscore seipin's critical roles in both metabolic and neurological systems.