Batten disease is a rare, fatal neurodegenerative lysosomal storage disorder predominantly affecting children. It arises from mutations in any one of thirteen known ceroid neuronal lipofuscinosis (CLN) genes, several of which have poorly understood molecular functions. In this talk, I will present recent findings from our laboratory, along with published evidence from other research groups, demonstrating that multiple CLN genes encode proteins collaboratively involved in synthesising bis(monoacylglycero)phosphate (BMP). BMP is a phospholipid uniquely localised in lysosomes, and essential for their proper functioning. Our findings indicate that BMP deficiency may be a fundamental driver of neurodegeneration in Batten disease, positioning BMP as a key component in lysosome-mediated neurodegenerative pathways. Additionally, these insights suggest novel therapeutic strategies aimed at restoring lysosomal BMP levels to improve Batten disease pathology.