A systematic review and meta-analysis examined data from 325 patients with T1DM treated with metformin as adjuvant to insulin therapy [86] .The authors concluded that metformin has no benefit in improving glycemic control but it can lead to modest reduction in the total daily dose of insulin and the BMI, which suggests that metformin could be helpful in decreasing weight gain associated with insulin use and indirectly improve cardiovascular risk of youth with T1DM [86]. The gene discussed is INS; the disease is type 1 diabetes mellitus.