C7 and hyperinsulinemic hypoglycemia, familial, 4: Due to the rarity and clinical significance of C7 deficiency, the aim of the current study was to report the case of a ten-year-old child with C7 deficiency, who was found to bear a novel mutation in C7 gene, and to perform a systematic review about the genetic bases of C7 deficiency to compare the genetic features of our case with those previously described in the literature.