Three single nucleotide polymorphisms were associated with increased diabetes risk (rs10517086_A [<i>P</i> = 0.03], rs1534422_G [<i>P</i> = 0.006], and rs2327832_G [<i>P</i> = 0.03] in <i>TNFAIP3</i>) and one with decreased risk (rs1004446_A in <i>INS</i> [<i>P</i> = 0.006]).
We identified one missense mutation (G32S) in the INS gene and two mutations (R131Q and R203S) in the HNF1α gene that could be associated with diabetes.
In type 1 diabetic patients, we found the INS mutation c.163C>T (R55C) in a girl who at 10 years of age presented with ketoacidosis and insulin-dependent, GAD, and insulinoma-associated antigen-2 (IA-2) antibody-negative diabetes.
A heterozygous R6C mutation cosegregated with diabetes in a MODY family and is probably pathogenic, but the L68M substitution identified in a patient with young-onset type 2 diabetes may be a rare nonfunctional variant.