If we used the reference range of the laboratory where the samples were tested (PTH: 1.3–9.3 pmol/L), the prevalence of secondary hyperparathyroidism would be 32.56%, 12.35% and 11.68% among adolescents with vitamin D severe deficiency, deficiency and insufficiency, respectively. The gene discussed is PTH; the disease is hyperinsulinemic hypoglycemia, familial, 4.