title: Newborn screening for methylmalonic aciduria by tandem mass spectrometry: 7 years' experience from two centers in Taiwan.
abstract: BACKGROUND
  The clinical course of methylmalonic aciduria (MMA) is fulminant in neonates and emergency management is necessary to save lives. It is therefore very important to differentiate affected from unaffected neonates immediately when there are abnormal results regarding MMA in newborn screening.
  
  
  METHODS
  Between January 2002 and December 2008, 598,522 newborns were screened for MMA by 2 neonatal screening centers: the Chinese Foundation of Health and the Taipei Institute of Pathology. A total of 22 newborns were referred to confirmatory medical centers, and 7 were confirmed as having MMA. The initial propionylcarnitine (C3) level, C3/acetylcarnitine (C2) ratio, plasma ammonia, liver function tests, blood pH and bicarbonate were compared between the true-positive and false-positive groups.
  
  
  RESULTS
  The C3/C2 ratio and plasma ammonia were markedly higher in the true-positive MMA group (p < 0.0001). Blood gas pH (p = 0.029), bicarbonate (p = 0.019), and aspartate aminotransferase (p = 0.005) also significantly differed between these 2 groups.
  
  
  CONCLUSIONS
  Referred newborns with elevated plasma C3/C2 ratios > 0.4 or ammonia levels > 200 mg/dL should be highly suspected of having MMA.
authors.affiliation: Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan, ROC.
authors.forename: Kang-Hsiang
authors.initials: KH
authors.lastname: Cheng
authors.forename: Mei-Ying
authors.initials: MY
authors.lastname: Liu
authors.forename: Chuan-Hong
authors.initials: CH
authors.lastname: Kao
authors.forename: Yann-Jang
authors.initials: YJ
authors.lastname: Chen
authors.forename: Kwang-Jen
authors.initials: KJ
authors.lastname: Hsiao
authors.forename: Tze-Tze
authors.initials: TT
authors.lastname: Liu
authors.forename: Hsiang-Yu
authors.initials: HY
authors.lastname: Lin
authors.forename: Cheng-Hung
authors.initials: CH
authors.lastname: Huang
authors.forename: Chuan-Chi
authors.initials: CC
authors.lastname: Chiang
authors.forename: Huey-Jane
authors.initials: HJ
authors.lastname: Ho
authors.forename: Shuan-Pei
authors.initials: SP
authors.lastname: Lin
authors.forename: Ni-Chung
authors.initials: NC
authors.lastname: Lee
authors.forename: Wuh-Liang
authors.initials: WL
authors.lastname: Hwu
authors.forename: Ju-Li
authors.initials: JL
authors.lastname: Lin
authors.forename: Ping-Yao
authors.initials: PY
authors.lastname: Hung
authors.forename: Dau-Ming
authors.initials: DM
authors.lastname: Niu
mesh_terms: D000108:Acetylcarnitine / Q000097:blood; D000641:Ammonia / Q000097:blood; D002331:Carnitine / Q000031:analogs & derivatives / Q000097:blood; D006801:Humans; D007231:Infant, Newborn; D008764:Methylmalonic Acid / Q000652:urine*; D015997:Neonatal Screening / Q000379:methods*; D013624:Taiwan; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: C003223:propionylcarnitine; D000108:Acetylcarnitine; D000641:Ammonia; D008764:Methylmalonic Acid; D002331:Carnitine