DNAJC5 and adult neuronal ceroid lipofuscinosis: Kufs disease/CLN4 is an autosomal dominant neurodegenerative disorder caused by unknown mechanisms through Leu115Arg and Leu116Δ mutations in the DNAJC5 gene that encodes the synaptic vesicle co-chaperone cysteine string protein α (CSPα/DNAJC5).