MLH1 and hyperinsulinemic hypoglycemia, familial, 4: In addition, dMMR group revealed 52.2% (n = 12/23) as single protein deficiency (MLH1), 13.0% (n = 3/23) as double protein deficiency (MLH1 + MSH2) and 4.3% (n = 1/23) as triple protein deficiency (MLH1 + MSH2 + MSH6).