Due to the fact that Tbx5 haploinsufficiency underlies the pathogenesis of Holt-Oram syndrome in humans, a congenital disease characterized by cardiac septation defects [91], further studies are required to assess the function of the miR-218 – Tbx5 regulatory circuit in vertebrate heart morphogenesis and patterning. The gene discussed is TBX5; the disease is Holt-Oram syndrome.