Application value of C14∶1/C12∶1 for very long chain acyl-CoA dehydrogenase deficiency in newborn screening / 中华检验医学杂志

ABSTRACT

Objective:To establish the cut-off value of tetradecenoyl carnitine (C14∶1)/dodecenoyl carnitine(C12∶1) based on non-derivatized tandem mass spectrometry (MS/MS), and to explore the application value of C14∶1/C12∶1 to screen newborns for very long chain acyl-CoA dehydrogenase deficiency (VLCADD), determining the best combination of indicators for screening VLCADD.Methods:This retrospective study included data from 17 newborns with VLCADD detected by MS/MS and confirmed by acyl-CoA dehydrogenase very long chain ( ACADVL) gene detection, and 423 507 newborns with normal MS/MS results. The data from these newborns were collected from January 2014 to December 2021 as the newborns received neonatal screening in Nanjing Neonatal Disease Screening Center and Suzhou Neonatal Disease Screening Center. All newborns were divided into 3 groups: all newborns group, full-term newborns group and normal-birth-weight newborns group, and the cut-off values of C14∶1/C12∶1 for VLCADD in these 3 groups were determined by their receiver operating characteristic (ROC) curves individually. With these results, a total of 5 interpretation schemes were composed using different indicators alone or jointly: scheme 1 being C14∶1/C12∶1, scheme 2 being C14∶1, scheme 3 being C14∶1+C14∶1/C2+C14∶1/C16, scheme 4 being C14∶1/C12∶1+C14∶1, and scheme 5 being C14∶1/C12∶1+C14∶1+C14∶1/C2+C14∶1/C16. The detection rate, false-positive rate and positive predictive value of each scheme were calculated, and their screening efficiencies were statistically compared by Chi-square tests. Results:The cut-off values of C14∶1/C12∶1 for VLCADD in the 3 newborn groups were all 2.80. The detection rates of VLCADD with all 5 interpretation schemes were 17/17. Scheme 1 had the highest false positive rate [26.15‰ (11 075/423 524)] and the lowest positive predictive value [0.15% (17/11 092)]. Scheme 4 (Scheme 5) had the lowest false positive rate [0.02‰ (10/423 524)] and the highest positive predictive value [62.96% (17/27)]. Comparing scheme 4 (Scheme 5) with scheme 1, scheme 2 and scheme 3, the differences of false positive rate (χ2=302.30,11 191.50,32.06) and positive predictive value (χ2=102.51,3 485.61,13.83) were statistically significant (all P<0.001). Conclusion:C14∶1/C12∶1 was an effective auxiliary interpretive indicator for VLCADD in newborn screening, and the combination of C14∶1/C12∶1+C14∶1 was tested to be the best indicator for VLCADD screening based on non-derivatized tandem mass spectrometry.