Extensive in vivo studies using [1‐13C]‐galactose demonstrated that individuals with GALT deficiency oxidized an average of 4% of a given dose in 5 hours (compared to around 40% in controls) and eliminated approximately 17% to 50% of a 7 mg/kg bolus dose in 24 hours.19, 20, 21, 22, 23. The gene discussed is GALT; the disease is hyperinsulinemic hypoglycemia, familial, 4.