Galactosemia is a group of rare genetic metabolic disorders characterized by impaired galactose metabolism resulting in a range of variable manifestations encompassing a severe, life-threatening disease (classic galactosemia), a rare mild form (galactokinase deficiency) causing cataract, and a very rare form with variable severity (galactose epimerase deficiency) resembling classic galactosemia in the severe form. The disease is MONDO_0018116 (galactosemia). Also known as: galactosaemia, galactose intolerance.