CLN6 is an endoplasmic reticulum (ER) transmembrane protein that functions as a critical component of the EGRESS (ER-to-Golgi relaying of enzymes of the lysosomal system) complex 1. CLN6 interacts with CLN8 to recruit lysosomal enzymes at the ER and promote their transport to the Golgi complex for subsequent lysosomal delivery 1. The protein's second luminal loop is essential for enzyme recruitment but dispensable for CLN8 binding 1. CLN6 deficiency results in inefficient ER export of lysosomal enzymes and diminished lysosomal enzyme levels, impairing lysosome biogenesis 1. Mutations in CLN6 cause neuronal ceroid lipofuscinosis (NCL), commonly known as Batten disease, an autosomal recessive lysosomal storage disorder 2. Disease presentations include progressive motor decline, cognitive impairment, visual loss, seizures, and myoclonus, with variable onset from early childhood to adulthood 23. Pathologically, CLN6-related disease features neuron loss predominantly in cerebral and cerebellar cortices with lipopigment accumulation in neural and extracerebral tissues 4. Glial activation precedes neuronal loss, progressing from visual cortex to widespread brain regions 5. Gene therapy approaches using AAV vectors expressing CLN6 show promise, preventing pathological hallmarks and extending survival in mouse models 6.