PHGDH and Alzheimer disease: Le Douce et al. (2020[4]) found that 6-month-old female triple-transgenic AD model mice (3xTg-AD mice) did not present significant reduction of hippocampal Phgdh expression in comparison with age-matched controls, as well as a dramatic decline of brain Phgdh levels in intermediate AD and advanced AD patients of 62 % and 82 %, respectively.