Compared with the natural history of treatment-naïve patients with MCT8 deficiency, body height-for-age improved (> 0.25 SD increase compared to the natural history reference) in 27 (63%) of 43 patients upon treatment and remained stable (−0.25 to 0.25 SD change compared with the natural history reference) in 7 (16%) of 43 patients (Supplementary Figure 5A (12)). Here, SLC16A2 is linked to hyperinsulinemic hypoglycemia, familial, 4.