HNF4A and Parkinson disease: We identified SHP1 (small heterodimer partner 1, NR0B2), a corepressor of NEURO D (NEUROD1) that competes with coactivator p300 for binding sites [43], and another repressor protein DAX (NR0B1) [44] that represses the activity of another gene; hepatocyte nuclear factor 4 (HNF4) [45, 46], previously identified as a potential biomarker for PD [47].