Newborn Screening for Methylmalonic Aciduria by Tandem Mass Spectrometry: 7 Years' Experience From Two Centers in Taiwan

Received 12 January 2010; accepted 26 February 2010.

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.

Conclusion

Referred newborns with elevated plasma C3/C2 ratios > 0.4 or ammonia levels > 200 mg/dL should be highly suspected of having MMA.

Key Words: methylmalonic aciduria , newborn screening , Taiwan , tandem mass spectrometry

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a Department of Pediatrics, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C.

b Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan, R.O.C.

c Institute of Genetics, School of Life Sciences, Taipei, Taiwan, R.O.C.

d VYM Genome Research Center, Taipei, Taiwan, R.O.C.

e Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan, R.O.C.

f Department of Pediatrics, Far Eastern Memorial Hospital, Taipei, Taiwan, R.O.C.

g Department of Pediatrics, Renai Branch, Taipei City Hospital, Taipei, Taiwan, R.O.C.

h Department of Pediatrics, Mackay Memorial Hospital, Taipei, Taiwan, R.O.C.

i Neonatal Screening Center, Chinese Foundation of Health, Taipei, Taiwan, R.O.C.

j Section of Newborn Screening, Taipei Institute of Pathology, Taipei, Taiwan, R.O.C.

k Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan, R.O.C.

l Department of Pediatrics, Chang Gung Children's Hospital, Taoyuan, Taiwan, R.O.C.

m Association of Congenital and Inherited Metabolic Disease, Taipei, Taiwan, R.O.C.

Correspondence to: Dr Dau-Ming Niu, Department of Pediatrics, Taipei Veterans General Hospital, 201, Section 2, Shih-Pai Road, Taipei 112, Taiwan, R.O.C.

† Kang-Hsiang Cheng and Mei-Ying Liu contributed equally to this work.

PII: S1726-4901(10)70067-8

doi:10.1016/S1726-4901(10)70067-8

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