|Home | About | Journals | Submit | Contact Us | Français|
The use of tandem‐mass spectrometry for neonatal screening has increased greatly in the last 10 years. In Australia all infants are screened in this way and the disorders most frequently diagnosed are medium‐chain acyl‐CoA dehydrogenase (MCAD) deficiency and phenylketonuria. There are few reports of outcomes after screening for rare disorders, but a nationwide Australian study of the effectiveness of screening by tandem‐mass spectrometry for MCAD deficiency has now been reported (Bridget Wilcken and colleagues. The Lancet 2007;369:37–42; see also Comment, ibid: 5–6).
The study included 2495000 infants born between April 1994 and March 2004, of whom 810000 were screened. The main cohort consisted of 1995000 infants (460000 screened) born between 1994 and March 2002 and followed up for at least 4 years. In addition, data were available for 500000 infants (350000 screened) born between April 2002 and March 2004. In the main cohort, MCAD deficiency was diagnosed in 2.3 per 100000 infants in the unscreened population and in 5.2 per 100000 in the screened population. The median age at diagnosis was 16 months in unscreened and 0.5 months in screened infants. Up to the age of 4 years among the unscreened population there were five deaths and 18 children had an episode of non‐fatal severe decompensation. Among the screened population there was one death and two children had non‐fatal severe decompensation. Conservative estimates of the relative risks of an adverse event (screened vs unscreened infants) were 0.44 in the main cohort by the age of 4 years and 0.26 in the whole cohort of 2495000 infants by the age of 2 years. Neuropsychological testing of 19 screened and 19 unscreened patients showed no significant differences between the two groups. There were no known false negative screening tests and screening gave an overall false positive rate of 0.01% and a positive predictive value of 42%.
Neonatal screening for MCAD deficiency is effective in that with appropriate management the risks of death or severe adverse events up to the age of 4 years are reduced.