STOX1 (Storkhead box 1), also known as PEE4 or C10orf24, is a winged-helix domain containing transcription factor believed to play a role in the differentiation of stem cells. As a DNA-binding protein, STOX1 exists as three alternatively spliced isoforms, designated A, B and C, all of which localize to either the cytoplasm or the nucleus. Defects in STOX1 are the cause of pre-eclampsia/eclampsia 4 (PEE4), also known as gestational proteinuric hypertension. STOX1 was also found to be functionally involved in late-onset Alzheimer's disease.