IRX6 is a transcription factor belonging to the Iroquois homeobox gene family that plays critical roles in neuronal development and differentiation 1. As a transcription factor, IRX6 binds to DNA and regulates gene expression, functioning as both an activator and repressor depending on context. In retinal development, IRX6 is specifically required for the terminal differentiation of bipolar interneuron subtypes, particularly type 2 and type 3a OFF bipolar cells 2. IRX6 directly regulates expression of cell type-specific markers including neurokinin 3 receptor (Nk3r) and Vsx1, and prevents aberrant adoption of molecular features between bipolar cell subtypes 2. In spinal cord development, IRX6 expression is confined to ventral domains and serves as a molecular marker for specific motor neuron groups, with HOX proteins directly controlling IRX6 expression 1. Clinically, IRX6 genetic variations are associated with congenital malformations including hypospadias, where polymorphisms in IRX6 increase disease susceptibility 34. Additionally, duplications affecting the IRXB gene cluster containing IRX6 cause autosomal dominant cone dystrophy with characteristic tritanopic color vision defects 5. IRX6 has also been implicated in rare epileptic encephalopathies like Landau-Kleffner syndrome 6.