This is the second case where this particular <i>KCNJ11</i> mutation has been incorrectly associated with diffuse <sup>18</sup>F-DOPA uptake, in contrast to the correct diagnosis of focal CHI confirmed by pancreatic biopsy.<h4>Conclusions</h4>Identifying discrepancies between genetic and imaging investigations is crucial as this may negatively impact upon the diagnosis and surgical treatment of focal CHI. Here, KCNJ11 is linked to congenital isolated hyperinsulinism.