MTHFR and hyperinsulinemic hypoglycemia, familial, 4: Null Mthfr−/− mice have been found to have abnormalities in the size and/or structure of the cerebellum, cortex and hippocampus, and to exhibit memory impairment and other behavioral anomalies reminiscent of those encountered in patients with severe MTHFR deficiency (Chen et al., 2001, 2005; Jadavji et al., 2012).