CTBS encodes chitobiase, a reducing-end exoglycosidase that catalyzes the degradation of N-linked glycans. The enzyme hydrolyzes N,N'-diacetylchitobiose and higher chitin-oligosaccharides to release monomeric N-acetylglucosamine (GlcNAc) from the reducing end of chitobiose units, functioning downstream of glycosylasparaginase in the N-linked glycoprotein degradation pathway. This catabolic process occurs primarily within lysosomes. CTBS is associated with multiple disease contexts including transient neonatal diabetes mellitus type 2, maturity-onset diabetes of the young types 2-4 and type 10, gestational diabetes, colitis, hepatocellular carcinoma, and hyperinsulinism due to glucokinase deficiency. The gene's involvement in these diverse metabolic and inflammatory conditions suggests that dysregulation of glycan degradation may contribute to both endocrine and hepatic pathology, though the precise mechanisms linking CTBS dysfunction to these phenotypes remain incompletely characterized.