The term Inborn Errors of Metabolism was used for the first time by Sir Archibald Garrod in his speech at the Royal College of Physicians of London reffering to the first 4 diseases to be classified in this group.Today more than 500 different Inborn Errors of Metabolism have been described,a number that is continuously increasing.It is estimated that 20% of the hereditary genetic diseases are metabolic disorders.They are classified in the group of rare disases since each individual defect is rare.However their overall frequency is at least 1:2000 births.Their number,the complexity and the diversity of their clinical presentation constitute a major challenge for every clinical doctor and scientist. Overall they are chronic diseases with particularly serious clinical phenotypes that impact on the survival a well as the quality of life of patients and their families.Their clinical symptoms can present from the intrauterine life through to adulthood, affecting all systems(nervous, muscular, cardiovascular, skeletal etc) Serious learning disabilities, psychomotor and/or intellectual delay or regression, as well as other serious neurological deficits are common clinical manifestations of these disorders.


Their accurate and timely diagnosis depends on the awareness of the clinical doctors and the existence of specialized laboratory infrasrtucture.Although for many inborn errors of metabolism specific treatment is still not available the developments in this area have been fascinating providing treatment opportunities to an increasing number of disorders.Appropiate and timely therapeutic intervention ,when available,is crucial for preventing the death of patients as well as the development of permanent neurological and other deficits