maple syrup urine disease

Maple syrup urine disease (MSUD) is an autosomal recessive disorder caused by mutations in the BCKDHA, BCKDHB, DBT, and DLD genes, leading to a deficiency of branched-chain alpha-keto acid dehydrogenase complex. This results in the accumulation of branched-chain amino acids and their toxic metabolites in the body. Symptoms typically manifest in infancy, including lethargy and developmental delays, and can progress to seizures, coma, and death if untreated. The condition is characterized by a distinctive sweet odor in the urine, reminiscent of maple syrup.

Documentation on maple syrup urine disease is limited due to its extreme rarity, with a prevalence of 1-9 in 1,000,000. The genetic basis was identified relatively recently, and systematic clinical studies have been sparse. This has resulted in a lack of comprehensive phenotype documentation, making it challenging to characterize the full clinical spectrum of the disease.

Currently, there are two orphan drugs designated for maple syrup urine disease: a modified version of a leucine decarboxylase enzyme derived from Planctomycetaceae bacterium and sodium phenylbutyrate. There are also seven active clinical trials investigating various aspects of the disease. For more details, you can explore these trials at ClinicalTrials.gov: https://clinicaltrials.gov/search?cond=maple%20syrup%20urine%20disease.