AGA (aspartylglucosaminidase) is a lysosomal hydrolase that cleaves the GlcNAc-Asn bond linking oligosaccharides to asparagine-linked glycoproteins, enabling protein deglycosylation 1. The enzyme catalyzes the degradation of glycoasparagines and related glycoconjugates within lysosomes, with activity detected in multiple cellular compartments including lysosomes, the endoplasmic reticulum, and extracellular spaces 1. Deficiency of AGA enzyme activity causes aspartylglucosaminuria (AGU), a recessively inherited lysosomal storage disease characterized by accumulation of undegraded glycoasparagines in tissues and body fluids 1. AGU is the most common disorder of glycoprotein degradation with high prevalence in Finnish populations, where a C163S mutation accounts for 98% of cases 1. The disease manifests as progressive intellectual and physical disability, macrocephalia, growth abnormalities, and typically leads to death before age 50 1. Clinically, enzyme replacement therapy with recombinant AGA has shown promise in animal models, reducing aspartylglucosamine accumulation in brain tissue by up to 40% 1. However, enzyme replacement trials in human AGU patients have not been reported, and alternative approaches such as allogeneic stem cell transplantation have proven ineffective 1. AGA-deficient mice share clinical, histopathologic, and biochemical characteristics with human AGU, providing valuable disease models for therapeutic development.