As such, we used leukocytes as a cellular model for analyzing alterations in the expression of genes related to insulin signaling, such as INSR, IRS1, IRS2, and PIK3R1, and those related to glucose transport, such as SLC2A1, SLC2A3 and SLC2A4, in women with GDM at the time of GDM diagnosis and 1-year postpartum. The gene discussed is IRS1; the disease is gestational diabetes.