CTNS and hyperinsulinemic hypoglycemia, familial, 4: Indeed, the acute down-regulation of cystinosin induced in HK2 cells with specific siRNA allowed us to explore direct consequences of cystinosin deficiency limiting, on the one side, the effects related to inter-individual variability, which is intrinsic to the study of patients-derived (or animal model-derived) cells [19], and, on the other side, effects linked to adaptation phenomena to cystinosin deficiency, which are likely to be less developed in CTNS KD cells compared to cells derived from patients or from Ctns-/- mice tissue.