EFO_0009081 (Heterotaxia) (coming from the Greek 'heteros' meaning different and 'taxis' meaning arrangement) is the right/left transposition of thoracic and/or abdominal organs. It encompasses a wide variety of disorders since there are multiple possibilities of right/left reversals, which may be complete (situs inversus totalis or situs inversus i.e. all the organs normally found on the right are on the left and vice versa) or partial (incomplete situs inversus i.e. a limited number of organs are inversed - or situs inversus ambiguous i.e. a normally lateral organ is centrally located). Also known as: Heterotaxy syndrome, Lateralization defect, Visceral heterotaxy.