Summary​​

 Introduction: the goal of newborn screening programmes is to ensure the presymptomatic identification and early treatment of treatable congenital disorders, in order to reduce morbiditymortality and possible disabilities associated with these diseases. Such programmes must guarantee equitable and universal access for all newborns in the target population, and provide accurate information to parents so as to help them with their decision-making. The introduction of mass spectrometry marks a radical change in the screening of metabolic diseases because, as compared to conventional methods, a high number of analytes associated with metabolic diseases can be detected by just one analytical procedure. Nevertheless, newborn screening should not be initiated, unless the advantages to the newborn of early detection have been clearly defined and guarantees are in place to ensure appropriate diagnosis, follow-up and treatment of all children detected by the health-care system.

 Objectives: to assess the clinical effectiveness of newborn screening of the following diseases, i.e., methylmalonic acidemia, propionic acidemia and tyrosinaemia type 1.

 Methods: systematic literature review of the principal biomedical databases (Medline, Embase, Cochrane Library Plus, Health Technology Assessment, Database of Abstracts of Reviews of Effects, National Health Service Economic Evaluation Database, ISI Web of Science and Índice Médico Español, among others). Two search strategies were used, one centred on epidemiology, natural history, morbidity, mortality, diagnosis and treatment, and the other centred on the screening of the disease.
To retrieve all existing systematic reviews and assessment reports on inborns errors of metabolism screening programmes, we updated the bibliographic search of the avalia-t report from 1 January 2006 to June 2013. After reading the abstracts of the resulting papers, studies were selected on the basis of a series of inclusion/exclusion criteria. Subsequently this procedure was completed by a manual review of the bibliographic references cited in the papers selected.

 Results, discussion and conclussion: See pdf below.