The known pathophysiology, together with recent data, illustrate the rationale for treatment of SHPT and vitamin D insufficiency/deficiency in non-dialysis CKD, and the KDIGO guidelines for the management of CKD-mineral and bone disorder recommend that patients with CKD stage G3–G4 and progressively rising or persistently elevated PTH levels above the upper limit of normal should be evaluated for vitamin D deficiency as one of the modifiable risk factors [7]. The gene discussed is PTH; the disease is hyperinsulinemic hypoglycemia, familial, 4.