ARSG (arylsulfatase G) is a lysosomal sulfatase enzyme that plays a critical role in heparan sulfate degradation. The protein consists of 525 amino acids with high sequence similarity to other arylsulfatases, particularly arylsulfatase A, and contains conserved catalytic site amino acids 1. ARSG specifically catalyzes the hydrolysis of 3-O-sulfate groups from N-sulfo-D-glucosamine 3-O-sulfate units within heparan sulfate during lysosomal degradation 2. The enzyme localizes to the endoplasmic reticulum as a 70 kDa mature glycosylated protein and shows ubiquitous expression 1. Pathogenic variants in ARSG cause Usher syndrome type IV, a rare form of deafblindness characterized by late-onset retinitis pigmentosa with pericentral and macular changes, and progressive sensorineural hearing loss without vestibular dysfunction 34. Functional studies demonstrate that disease-causing mutations result in complete loss of sulfatase enzymatic activity 34. The sequential action of ARSG with other sulfatases is essential for proper lysosomal catabolism of sulfated heparan sulfate 2. Additionally, genetic variants in ARSG have been associated with blood pressure regulation in Korean populations 5.