Newborn Screening for MCAD Deficiency Experience of the First Three Years in British Columbia,
Bibliographic record
Abstract
Background: Medium Chain Acyl-CoA Dehydrogenase (MCAD) Deficiency is an autosomal recessive disorder of fatty acid oxidation, with potential fatal outcome. MCAD deficiency is diagnosed by acylcarnitine analysis on newborn screening blood spot cards by tandem mass spectrometry. Early diagnosis of MCAD and presymptomatic treatment can potentially reduce morbidity and mortality. Objectives: To evaluate incidence, clinical outcome, biochemical and molecular phenotype of MCAD cases detected in the first three years of newborn screening in British Columbia (BC). Methods and Results: Medium chain length acylcarnitines, octanoylcarnitine (C8) and decanoylcarnitine (C10), were measured on newborn screening blood spot cards. Out of 121,000 live births, 17 newborns had C8 values above the screening cut-off of 0.38 umol/L. Ten newborns had elevated C8 on repeat cards and were investigated further. Both C8 and C8/C10 ratios remained abnormal in all confirmed MCAD cases. Positive predictive value of screening was 58 % with no false negative results. Seven patients were homozygous for the common c.985A>G MCAD mutation and three others were compound heterozygous for the c.985A>G and a second mutation. Two novel mutations were identified (c.260T>C and c.382T>A). The estimated incidence of MCAD was ~1:12,000 live births. Upon frequent feeding and carnitine supplementation, none of the patients had metabolic crises or adverse outcomes. Conclusion: Frequency of MCAD in BC is comparable to reports from other newborn screening programs. Persistence of elevated C8 levels and C8/C10 ratios in confirmed MCAD cases suggest that these are sensitive markers for newborn screening. Early detection and treatment have successfully prevented adverse health outcomes in patients with MCAD. Key words: Neonatal screening; fatty acid oxidation complex; Acyl-CoA dehydrogenase; medium chain Acyl-CoA dehydrogenase; sudden infant death
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.002 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".