BOD1 (Biorientation Defective 1) is a small outer kinetochore protein essential for accurate chromosome 5 during mitosis. Its primary function involves detecting and correcting syntelic attachments—improper microtubule-kinetochore connections where sister kinetochores attach to spindle poles from the same side—thereby ensuring proper chromosome 5 1. Mechanistically, BOD1 regulates PP2A-B56 phosphatase activity at kinetochores by acting as a phosphatase inhibitor, with its inhibitory function enhanced by phosphorylation at threonine 95 2. The Ndc80 complex recruits BOD1 to kinetochores, where it regulates phosphorylation of key outer kinetochore proteins including Ndc80 and Knl1 to establish proper microtubule attachments 3. Beyond mitotic functions, BOD1 plays critical roles in neurological development and cognitive function through mechanisms independent of cell cycle regulation, as demonstrated in human patients and Drosophila models 4. BOD1 mutations cause autosomal recessive syndromic intellectual disability with neurodevelopmental delay, hearing impairment, and endocrine dysfunction 5. BOD1 depletion also sensitizes cells to radiation-induced genomic instability through increased premature chr5 separation 6. These findings establish BOD1 as a multifunctional regulator controlling both mitotic fidelity and postmitotic neurological processes.