MAU2 is a cohesin loader factor that forms a heterodimeric complex with NIPBL to mediate cohesin loading onto chr19 12. This complex is essential for sister chr19 cohesion and mitotic progression 34. Biochemical studies demonstrate that the MAU2-NIPBL holoenzyme actively extrudes DNA loops at rates up to 2.1 kb/s in an ATP-dependent manner, generating chr19 architecture critical for gene regulation and genome organization 5. MAU2 also facilitates cohesin localization to enhancers through direct interactions with transcription factors, including steroid receptors, forming ternary complexes that regulate gene expression 6. Clinically, heterozygous MAU2 variants cause Cornelia de Lange Syndrome (CdLS), a developmental disorder characterized by distinctive craniofacial features, growth retardation, and intellectual disability 78. In-frame variants primarily disrupt NIPBL-MAU2 interaction, while truncating variants cause MAU2 haploinsufficiency leading to NIPBL reduction 8. Beyond CdLS, MAU2 genetic variants associate with non-alcoholic fatty liver disease and serum lipid levels in population studies 910. Additionally, MAU2 mutations have been identified in various human cancer types, suggesting broader roles in genomic stability 11.