Methylmalonic AcidVitamin B 12 DeficiencyMalonatesVitamin B 12Methylmalonyl-CoA MutaseTranscobalaminsAmino Acid Metabolism, Inborn ErrorsHomocysteineFolic AcidAtlantic IslandsHydroxocobalaminFolic Acid DeficiencyVitamin B ComplexPropionatesCystathionineMetabolism, Inborn ErrorsAnemia, PerniciousSuccinate-CoA LigasesCitratesGas Chromatography-Mass SpectrometryMethylmalonate-Semialdehyde Dehydrogenase (Acylating)Diet, VegetarianNutritional StatusHomocystinuriaIsoleucineSuccinic AcidAcyl Coenzyme APropionic AcidemiaSuccinatesDietary SupplementsBiological Markers