The divergent findings across species may be due to the fact that: (a) there are species differences in cognitive processes; (b) STS inhibition results in incomplete enzyme deficiency (and studies have only examined effects in adulthood) whereas genetic variants such as microdeletions result in complete STS loss throughout life; (c) compounds used as STS inhibitors can have off‐target and oestrogenic effects30; and/or (d) XLI‐associated genetic variants in man are typically 1.5–1.7 Mb in size and delete adjacent brain‐expressed genes. Here, STS is linked to hyperinsulinemic hypoglycemia, familial, 4.