Provided herein are methods and compositions for treatment of Batten disease. Such compositions include a recombinant adeno-associated virus (rAAV), said rAAV comprising an AAV capsid, and a vector genome packaged therein, said vector genome comprising (a) an AAV 5 inverted terminal repeat (ITR) sequence; (b) a promoter; (c) a CLN2 coding sequence encoding a human TPP1; (d) an AAV 3 ITR.