Docosahexaenoic acid status in females of reproductive age with maple syrup urine disease.

ABSTRACT

Individuals with maple syrup urine disease (MSUD) have impaired metabolism of branched-chain amino acids (BCAA) valine, isoleucine, and leucine. Life-long dietary therapy is recommended to restrict BCAA intake and thus prevent poor neurological outcomes and death. To maintain adequate nutritional status, the majority of protein and nutrients are derived from synthetic BCAA-free medical foods with variable fatty acid content. Given the restrictive diet and the importance of omega-3 fatty acids, particularly docosahexaenoic acid (DHA), in neurological development, this study evaluated the dietary and fatty acid status of females of reproductive age with MSUD attending a metabolic camp. Healthy controls of similar age and sex were selected from existing normal laboratory data. Total lipid fatty acid concentration in plasma and erythrocytes was analyzed using gas chromatography-mass spectroscopy. Participants with MSUD had normal to increased concentrations of plasma and erythrocyte alpha linolenic acid (ALA) but significantly lower concentrations of plasma and erythrocyte docosahexaenoic acid (DHA) as percent of total lipid fatty acids compared with controls (plasma DHA MSUD 1.03 +/- 0.35, controls 2.87 +/- 1.08; P = 0.001; erythrocyte DHA MSUD 2.58 +/- 0.58, controls 3.66 +/- 0.80; P = 0.011). Dietary records reflected negligible or no DHA intake over the 3-day period prior to the blood draw (range 0-2 mg). These results suggest females of reproductive age with MSUD have lower blood DHA concentrations than age-matched controls. In addition, the presence of ALA in medical foods and the background diet may not counter the lack of preformed DHA in the diet. The implications of these results warrant further investigation.