The utility of dried blood spot monitoring of branched-chain amino acids for maple syrup urine disease: A retrospective chart review study.

Background: Branched-chain amino acid (BCAA) concentrations must be tracked and maintained within an optimal range to minimize disease phenotypes in patients with maple syrup urine disease (MSUD). In 2014, the Hospital for Sick Children (SickKids) implemented a dried blood spot (DBS) home monitoring system, allowing patients to track BCAA concentrations without the inconvenience of having to travel to the hospital.

Methods: We conducted a retrospective chart review study (n = 15) to assess the impacts of DBS monitoring implementation on biochemical control. Furthermore, we explored relationships among various MSUD patient parameters, including monitoring frequency, age, biochemical control, and hospitalizations.

Results: There was a 35% increase in the proportion of LEU concentrations that met recommended targets post-DBS monitoring implementation. Monitoring frequency was positively associated with better biochemical control in the newborn period (r = 0.68, p = 0.046). Frequency of hospital visits decreased steadily throughout life.

Conclusion: DBS monitoring has resulted in a sharp increase in monitoring frequency, which is further correlated with biochemical control. Younger patients are more likely to visit the hospital and respond better to increased monitoring efforts. We recommend that DBS monitoring be adopted by other centers more broadly to improve metabolic control in MSUD patients.