Use of tandem mass spectrometry for newborn screening of 6 lysosomal storage disorders in a Korean population.
BACKGROUND
We evaluated the performance of multiplex tandem mass spectrometry (MS/MS) in newborn screening for detection of 6 lysosomal storage disorders (LSDs), namely, Niemann-Pick A/B, Krabbe, Gaucher, Fabry, and Pompe diseases and Hurler syndrome.


METHODS
We revised the conditions and procedures of multiplex enzyme assay for the MS/MS analysis and determined the precision of our enzyme assay and the effects of sample amounts and incubation time on the results. We also measured the degree of correlation between the enzyme activities in the dried blood spots (DBSs) and those in the leukocytes. DBSs of 211 normal newborns and 13 newborns with various LSDs were analyzed using our revised methods.


RESULTS
The intra- and inter-assay precisions were 2.9-18.7% and 8.1-18.1%, respectively. The amount of product obtained was proportional to the DBS eluate volume, but a slight flattening was observed in the product vs. sample volume curve at higher sample volumes. For each enzyme assay, the amount of product obtained increased linearly with the incubation period (range, 0-24 hr). Passing and Bablok regression analysis revealed that the enzyme activities in the DBSs and those in the leukocytes were favorably correlated. The enzyme activities measured in the DBSs were consistently lower in patients with LSDs than in normal newborns.


CONCLUSIONS
The performance of our revised techniques for MS/MS detection and enzyme assays was of the generally acceptable standard. To our knowledge, this is the first report on the use of MS/MS for newborn screening of LSDs in an Asian population.
Department of Laboratory Medicine, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam, Korea.
Minje
M
Han
Sun-Hee
SH
Jun
Sang Hoon
SH
Song
Kyoung Un
KU
Park
Jin Q
JQ
Kim
Junghan
J
Song
D059788:Dried Blood Spot Testing; D057075:Enzyme Assays; D004798:Enzymes / Q000097:blood; D006801:Humans; D007231:Infant, Newborn; D007962:Leukocytes / Q000201:enzymology; D016464:Lysosomal Storage Diseases / Q000175:diagnosis*; D056910:Republic of Korea; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013997:Time Factors
D004798:Enzymes