This result was not due to a significant difference in the allele frequency of CFHR3*Del between patients and controls, because when the 22 aHUS patients and the 2 controls with the CFHR3*Del/Del genotype and homozygous FHR-3 deficiency were excluded, a similar difference in FHR-3 levels was observed (2.28 ± 1.72 vs. 0.61 ± 0.24 μg/mL, p < 0.0001). This evidence concerns the gene CFHR3 and hyperinsulinemic hypoglycemia, familial, 4.