The LIM homeobox transcription factor 1 (LMX1A) belongs to the LIM-homeodomain family. Members of this family are known to be important for pattern formation during development. LMX1A binds an A/T-rich sequence and functions in the nucleus as a transcriptional activator to the insulin gene promoter. In the developing embryo, LMX1A is expressed along the neuraxis and leads to the development of the roof plate of the vertebrae. While LMX1A is crucial for the differentiation of dopamine neurons, the related LMX1B appears to be important for both the development and the survival of these cells. It has been sμggested that LMX1A might be a useful biomarker or risk factor in tumor aggressiveness.