Background: Generating evidence to inform care for pediatric medium-chain acyl-CoA dehydrogenase (MCAD) deficiency requires sustainable and integrated measurement of priority outcomes. Methods: From an existing Canadian cohort study, we evaluated the quality of metabolic clinic chart-abstracted data for measuring core outcomes for pediatric MCAD deficiency. We then modelled variation in emergency department (ED) use, in association with disease severity, child age, and distance to care. Results: Children with MCAD deficiency visit the metabolic clinic at least annually on average but we identified data quality challenges related to inconsistent definitions of core outcomes and missing information in patient charts. Rates of ED use were highest among children aged 6 to 12 months, with more severe disease, and living closest to care. Conclusion: While measuring core outcomes through the metabolic clinic for children with MCAD deficiency is feasible, harmonized data collection is needed to evaluate care and further understand ED use.

Sudden Infant Death (SIDS) has been associated with medium-chain acyl-CoA dehydrogenase (MCAD) deficiency, an inborn error of fatty acid oxidation. Blood and tissue samples from a large cohort of SIDS victims were analyzed for the presence of dodecanoic acid (C₁₂) by gas chromatography. A subgroup of these cases had a significantly higher blood concentration than age-matched controls, suggesting MCAD deficiency. An animal study using Sprague-Dawley rats was done to mimic the effects of MCAD deficiency. Significantly increased blood concentrations of dodecanoic acid were observed. Decreased values in heart and liver were puzzling findings. The data indicate that dodecanoic acid is a blood marker for MCAD deficiency.