QUANTIFICATION OF GLYCOSAMINOGLYICANS USING TANDEMMASSSPECTROMETRY FOR NEWBORN SCREENING OF MUCOPOLYSACCARIDOSES Kida K 1 , Fuji N 1 , Hirakiyama A 1 , Furujo M 2 , Kosuga M 1 , Okuyama T 1 1 Crin Lab Med, NCCHD, Tokyo, Japan 2 Nat Okayama Med Cent, Okayama, Japan Background: Mucopolysaccharidoses (MPSs) are a deficiency of lysosomal enzymes to digest Glycosaminoglycans (GAGs), such as dermatan sulfate (DS), heparan sulfate (HS), and keratan sulfate (KS). The accumulation of GAGs into lysosome induces various symptoms. As enzyme replacement therapy (ERT) and bone marrow transplantation bring successful result for patients in early stage of MPSs, we need a suitable method for newborn screening (NBS) for MPSs using. dried blood spot samples (DBS) on Guthrie cards. Material and Methods: We used a highly sensitive liquid chromatography tandem mass spectrometry (LC/MS/MS) to analyze the disaccharides digested from GAGs in DBS. We measured GAGs in Guthrie paper from normal control newborn and adult samples (n=200), newborn and several types of MPS patients (I: 2; II:5; III:2, IV:2, and VI:2).