Intermediate Maple Syrup Urine Disease (iMSUD) is a rare genetic disorder characterized by a deficiency in the enzyme branched-chain ketoacid dehydrogenase (BCKDH), which is responsible for breaking down amino acids called leucine, isoleucine, and valine. This metabolic condition leads to the accumulation of toxic byproducts, such as alpha-keto acids, in the body, resulting in various symptoms.
iMSUD is called intermediate due to the less severe nature compared to classical Maple Syrup Urine Disease (MSUD). It typically manifests later in infancy or childhood, and the severity of symptoms may vary among affected individuals. Common signs include poor feeding, vomiting, lethargy, developmental delays, growth retardation, muscle weakness, abnormal movements, intellectual disability, and a distinct odor of maple syrup in urine, sweat, and cerumen.
Diagnosis of iMSUD involves clinical evaluation, urine analysis, and blood tests to measure the levels of amino acids and their ketoacid derivatives. Genetic testing is often performed to confirm the presence of mutations in the genes responsible for BCKDH.
Treatment of iMSUD primarily revolves around dietary management. Individuals affected by iMSUD typically require a special low-protein diet restricting the intake of leucine, isoleucine, and valine. Supplementation of specific amino acids, such as threonine and glycine, is necessary to ensure proper growth and development. Regular monitoring of blood amino acid levels is essential to prevent metabolic crises and adjust the diet accordingly. With early diagnosis and proper management, individuals with iMSUD can lead relatively healthy lives, minimizing the risk of long-term complications.
