Tandem Mass Neonatal Screening in Taiwan—Report from One Center

Neonatal screening using tandem mass spectrometry (MS/MS) started in Taiwan in 2000. We evaluated the efficacy of this system by analyzing the frequency of diseases and the outcome of the patients identified. Methods: Between August 2001 and July 2004, 199,922 neonates were screened for 10 amino acids and acylcarnitines using MS/MS in a single center. Results: In total, 29 cases of inborn errors of metabolism were detected. The overall prevalence was one per 6894 births. The most common inborn error found was 3-methylcrotonyl CoA carboxylase deficiency (10 cases, 34.5%), but none of the cases needed aggressive treatment. There were two cases of type I glu-taric aciduria, two cases of maple syrup urine disease, and one case of type II citrullinemia, and early therapeutic intervention was effective for all of them. Conclusion: We found that MS/MS neonatal screening was valuable in the early diagnosis of severe and treatable inborn errors of metabolism such as organic acidemias and urea cycle disorders. It also detected less severe disorders that required only observation