The mean fasting C-peptide level was 1.2 ± 0.9 nmol/l and 12.3% of the participants had C-peptide < 0.26 nmol/l.***More than half of the participants had high C-peptide levels suggesting significant endogenous insulin secretion (C-peptide was measured 1 week from diabetes diagnosis). The gene discussed is INS; the disease is diabetes mellitus.