C4A and short chain acyl-CoA dehydrogenase deficiency: Among the neonates diagnosed with SCADD, the average blood C4 level was 1.44 ± 0.46 μmol/L (normal range: 0.08–0.49 μmol/L), with average values of C4/acetylcarnitine (C2), C4/propionyl carnitine (C3), C4/isovalerylcarnitine (C5), and C4/hexanoylcarnitine (C6) of 0.10 ± 0.05 (normal range: 0–0.03), 1.04 ± 0.53 (normal range: 0.04–0.40), 8.90 ± 3.59, and 41.57 ± 15.86, respectively.