NKX6-1 and hydrops fetalis: Furthermore, expression levels of genes encoding transcription factors that maintain β-cell identity, such as NKX2.2, NKX6.1, MAFA, PAX4, and PAX6 37, 38, as well as insulins, INS1 and INS2, were downregulated in islets of HF-fed Egr1-/- mice.