TPP1 and neuronal ceroid lipofuscinosis 2: We also measured α- and β-mannosidase activities in brain tissues from Dachshunds with neuronal ceroid lipofuscinosis 2 (CLN2 disease), an LSD due to lysosomal tripeptidyl peptidase-1 (TPP1) deficiency [28], and from a mixed breed hound with no known disease, which served as a normal control.