Newborn Screening of 6 Lysosomal Storage Disorders by Tandem Mass Spectrometry

This study was designed to screen 6 lysosomal storage diseases (LSDs) in neonates using tandem mass spectrometry (MS/MS), and establish cutoff values for these LSDs with 3000 dried blood spots (DBS) samples. Cutoff values for alpha-L-iduronidase (IDUA), alpha-galactosidase (GLA), acid beta glucosidase (ABG), beta-galactocerebrosidase (GALC), acid sphingomyelinase (ASM), and acid alpha glucosidase (GAA) were as follows: GLA, > 2.06 mu mol/L<middle dot>h; ABG, > 1.78 mu mol/L<middle dot>h; ASM, > 0.99 mu mol/L<middle dot>h; IDUA, > 1.33 mu mol/L<middle dot>h; GALC, > 0.84 mu mol/L<middle dot>h; and GAA, > 2.06 mu mol/L<middle dot>h. There were 30 positives in initial MS/MS screening test, and 15 samples were still positive with repeat testing. Their parents/guardians were recontacted and DBS samples were collected again for test. Only 1 child showed abnormal GAA enzyme activity after recontacting process, and was diagnosed with Pompe disease after genetic screening. Eventually, cutoff values of 6 specific enzyme activities were established and MS/MS is effective for early LSDs screening.