TABLE 1.

Genes associated with the NCL subtypes, as well as the localizations and molecular functions of proteins encoded by those genes.

Gene	NCL subtype	Disease onset	Localization of protein encoded by gene	Molecular function of protein
PPT1	CLN1 disease	Infantile	Lysosomal lumen	Protein thioesterase
		Late-infantile Juvenile	Extracellular
		Adult
TPP1	CLN2 disease	Late-infantile Juvenile	Lysosomal lumen	Serine protease
			Extracellular
CLN3	CLN3 disease	Juvenile	Lysosomal membrane	Not well defined a
			Endosomal membrane
			Golgi complex
DNAJC5	CLN4 disease	Adult	Perinuclear	Co-chaperone protein
			Lysosome
			Endo-lysosomal lumen
			Cytoplasm
			Plasma membrane
CLN5	CLN5 disease	Late-infantile Juvenile	ER	Glycoside hydrolase b
		Adult	Lysosomal lumen
		Extracellular
CLN6	CLN6 disease	Late-infantile Adult	ER membrane	ER-Golgi protein transport
MFSD8	CLN7 disease	Late-infantile	Lysosomal membrane	Not well defined
CLN8	CLN8 disease	Late-infantile	ER membrane	ER-Golgi protein transport
			Membranes between ER and Golgi
CTSD	CLN10 disease	Congenital	Lysosomal lumen Extracellular	Aspartyl endopeptidase
		Neonatal
		Late-infantile Juvenile
		Adult
GRN	CLN11 disease	Adult	Lysosomal lumen	Not well defined
			Extracellular
ATP13A2	CLN12 disease	Juvenile	Multivesicular bodies Lysosomal membrane	Not well defined
			Membranes of early and late endosomes
CTSF	CLN13 disease	Adult	Lysosomal lumen	Cysteine protease
			Extracellular
KCTD7	CLN14 disease	Infantile	Plasma membrane	Not well defined
TBCK	CLN15 disease	Infantile	Perinuclear Centrosome	Rab GTPase-activating protein

^aSee Cotman and Lefrancois (2021) for a recent review of CLN3-dependent processes.

^bSee Basak et al. (2021b) for a recent review of CLN5-dependent processes.