Tandem mass spectrometry detects inborn errors of metabolism

Tandem mass spectrometry (MS/MS) has been used in China to study a wide range of previously unscreened inborn errors of metabolism (IEM) using a single test.

The three-year pilot study investigated the screening, diagnosis, treatment and outcomes of IEM in symptomatic infants and children, finding that because most symptomatic patients are diagnosed at an older age, mental retardation and motor delay are difficult to reverse. Furthermore, the efficiency of treatment is greatly compromised by poor medication compliance.

Of the 11,060 symptomatic patients (6,720 boys, 4,340 girls) with a median age of 28.8 months that were screened,  62 were diagnosed with IEM, with a detection rate of 0.56 per cent. A further 35 were males and 27 females and the median age was 3.55 months (range 0.07-143.9 months). Of the 62 patients, 27 (43.5 per cent) had aminoacidemias, 26 (41.9 per cent) had organic acidemias and nine (14.5 per cent) had fatty acid oxidation disorders.

The study was conducted by taking dried blood spots from all children and analysing them by tandem mass spectrometry. All children encountered in the Newborn Screening Center of Zhejiang Province during a three-year period with symptoms suspicious for IEM were screened for metabolic diseases.

Published by Ben Evans