Maple Syrup Urine Disease
Pathogenesis (Amino Acid Disorder)
- Branched Chain Ketoacid Dehydrogenase inactivity leads to failure of breakdown of ketoacid products formed from branched chain amino acid breakdown (leucine, isoleucine, and valine), thus there is toxic accumulation of branched chain amino acids and their ketoacid products, which is lethal if untreated.
Clinical
- Onset: Birth
- Presentation: Poor Feeding/Lethargy/Vomiting, Urine smells sweet – Maple Syrup smell in urine and ear wax.
- Triggers: Catabolic stress response to illness (Infection, Fever, Surgery, etc…) or High Protein diet.
- Treatment: Cease Protein Intake, Eliminate Metabolites (Dialysis), Hydrate & Correct Metabolic Abnormalities
Genetics
- Multiple genes (including the MUT gene)
- Autosomal recessive
- Key Population: Mennonite (specifically, Old Order Mennonite)
References
- Calvo, Sherri; Collins, Heather; Greenberg, Kathleen, et. al at US National Library of Medicine, Genetics Home Reference. https://ghr.nlm.nih.gov