GLB1L2 encodes a galactosidase enzyme that probably cleaves beta-linked terminal galactosyl residues from gangliosides, glycoproteins, and glycosaminoglycans. While the gene exhibits beta-galactosidase activity and participates in galactose catabolism, functional studies indicate it is not essential for basic biological processes—male mice with GLB1L2 deletions (including a triple knockout of Glb1l2 and Glb1l3) maintain normal epididymal histology, sperm morphology, and male fertility 1. GLB1L2 has been associated with multiple complex genetic conditions. Genome-wide studies identified GLB1L2 as a recessive locus for non-syndromic cleft lip with or without cleft palate 2, and as a susceptibility gene for spina bifida through gene-based burden testing 3. The gene was also identified in novel copy number variants associated with tetralogy of Fallot in Han Chinese populations 4. Additionally, GLB1L2 methylation status shows epigenetic sensitivity to early-life exposures—differential DNA methylation at GLB1L2 was detected in association with maternal education in birth cohorts 5 and following infant RSV immunoprophylaxis 6. GLB1L2 expression was upregulated in clopidogrel-resistant coronary artery disease patients 7 and identified as part of a ferroptosis and immune-related gene signature for osteosarcoma prognosis 8.