Abstract
Failure-to-thrive has been described in patients with organic acidemia who are treated using a low-protein diet. We report very different courses of growth due to dietary treatment in two cases of organic acidemia (methylmalonic acidemia [MMA] and propionic acidemia [PA]). Both patients showed early onset, but the durations from the first symptom to the diagnosis and initiation of sufficient diet therapy differed. One case (MMA) exhibited metabolic acidosis and severe hyperammonemia for 5 days and from day 7 to 11, respectively. He was diagnosed on day 13, and was then started on a protein-restricted diet without essential amino acids. He currently exhibits a serious mental development delay and is short in stature (-2.6 SD). The other case (PA) had hyperammonemia for only 12 hours on day 7 and was diagnosed on day 8 by neonatal tandem-mass screening. She was started on a sufficient protein-restricted diet with essential amino acids and adequate energy immediately after diagnosis. She has shown no mental delay or failure-to-thrive (final height, -0.3 SD). We conclude that improved growth with organic acidemia can be expected with early diagnosis and early initiation of suitable nutrition management.
