Despite suspicions that YEL-AVD/YEL-AND may have a genetic component, there has been only one report of YEL-AND in an otherwise healthy adolescent with homozygous IFNAR1 deficiency [27••] and one report of YEL-AVD in IFNAR2 deficiency [71•]. This evidence concerns the gene IFNAR2 and hyperinsulinemic hypoglycemia, familial, 4.