demonstrated that the T-cell repertoire in CD3γ deficiency carries a molecular signature predisposing to autoimmunity, notably an enrichment of hydrophobic amino acids at positions 6 and 7 of the TRB-CDR3 region, a recognized biomarker of self-reactivity (24). The gene discussed is CD3G; the disease is hyperinsulinemic hypoglycemia, familial, 4.