Mutations in HNF1A, HNF4A, and HNF1β genes involved in Lp(a) expression account for more than 50% of monogenic diabetes with a known genetic cause, which may lead to the complexity of concentrations of Lp(a) in patients with T2DM (22, 25, 27, 28). The gene discussed is HNF1B; the disease is type 2 diabetes mellitus.