Inborn errors of metabolism

Cite this article as:
Tessa Davis. Inborn errors of metabolism, Don't Forget the Bubbles, 2020. Available at:
DisorderExamplesBasic pathophysiologyBlood gasAmmoniaGlucoseKetonesLactate
Urea cycle disordersOTC deficiencyDefect in breakdown of nitrogen → ammoniaRespiratory alkalosis/normal↑↑↑---
Amino acid disordersPKU, MSUD, homocystinuriaDefect in breakdown of amino acidsMetabolic acidosis (↑ anion gap)↑/-↑ (MSUD ↑↑↑ urinary ketones)-
Organic acid disordersPropionic, MMAAccumulation of organic acidsMetabolic acidosis (↑ anion gap)
Lysosomal storage disordersMPS, Pompe, Gaucher, Niemann-PickAccumulation of proteins/lipids-----
Glycogen storage disordersGSD types I-IXDefect in glycogen synthesisMetabolic acidosis-
Fatty acid oxidation disordersMCADD, LCADD, VLCADDUnable to break down fatty acids → ketonesMetabolic acidosis (↑ acidosis)--/↑
Mitochondrial disordersMELASInsufficient acetyl coA for Krebs cycle → ↓ ATPMetabolic acidosis--/↑-↑↑
Peroxisomal disordersXL, ADL, Refsum, Zellweger↓ metabolism of VLCFA, ↓ bile synthesis-----