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Propionic acidemia

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A newborn presents similarly to MMA with metabolic acidosis and hyperammonemia. Organic acids show elevated propionic acid and methylcitrate.

AR; PCCA or PCCB (propionyl-CoA carboxylase)

  • Similar presentation to MMA
  • Cardiomyopathy (more common than MMA)
  • Basal ganglia stroke
  • On RUSP
  • Newborn screening: elevated C3 (propionylcarnitine) on acylcarnitine profile (shared with methylmalonic acidemia)
  • Urine organic acids: elevated 3-hydroxypropionate, methylcitrate, propionylglycine; no methylmalonic acid (distinguishes from MMA)
  • Confirm with PCCA/PCCB molecular testing or propionyl-CoA carboxylase enzyme assay
  • Protein restriction, carnitine, metronidazole (reduces propionate-producing gut bacteria)

"Pump" in Propionic: PA patients develop issues with the Pump (cardiac disease/cardiomyopathy). Contrast with MMA, where patients develop issues with the kidney (Micturition in Methylmalonic).

NBS: High C3: elevated C3 (propionylcarnitine) on newborn screening acylcarnitine profile (same marker as MMA).

"PMS = Krabby Mood": the organic acid pathway is Propionyl-CoA, Methylmalonyl-CoA, Succinyl-CoA (enters the Krebs cycle). VoMIT amino acids (Valine, Methionine, Isoleucine, Threonine) are the dietary precursors to restrict.

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