Congenital absence of both forearm and hand, bilateral is a rare developmental defect during embryogenesis characterized by a bilateral, transverse absence of the radius and ulna (of varying terminal lengths), as well as all the elements composing the hand. The disease is congenital absence of both forearm and hand, bilateral (Monarch Disease Ontology term MONDO_0017499). Also known as: radio-ulnar terminal transverse meromelia, bilateral.