by Anne Marie Helmenstine, Ph.D. Updated June 13, 2014. Definition: A molecular orbital is an orbital or wavefunction of a molecule's electron. Electrons around a molecule can be associated with more than one atom and are often expressed as a combination of atomic orbitals.
Hereditary angioedema is a disorder characterized by recurrent episodes of severe swelling (angioedema). The most common areas of the body to develop swelling are the limbs, face, intestinal tract, and airway. Minor trauma or stress may trigger an attack, but swelling often occurs without a known trigger.
Angioedema-swelling of tissue beneath the surface of the skin-can be mistaken for or associated with hives. It can be caused by allergic reactions, medications or a hereditary deficiency of some enzymes. The following symptoms may indicate angioedema: 1  Swelling in the eyes or mouth. 2  Swelling of the hands, feet or throat. 3  Difficulty breathing, stomach cramps or chemosis (swelling of the lining of the eyes).