Babies with this condition can have serious health problems soon after birth if they are not diagnosed and treated quickly.įalse-positive newborn screening results for this condition can happen. You should complete any recommended follow-up testing as soon as possible. Your baby may need the following tests after an out-of-range screening result: To learn more about screening results, visit the Blood Spot Screening Results page. It does mean that your baby needs more follow-up testing. Together, you will discuss next steps and follow-up plans.Īn out-of-range screening result does not mean that your baby definitely has the condition. If your baby’s blood spot screening result for maple syrup urine disease is out-of-range, your baby’s health care provider will contact you. In severe cases, this condition can lead to coma or death if not diagnosed and treated early. Without treatment, toxic levels of branched-chain amino acids and their related substances can lead to the signs and symptoms of the condition. The substances the body cannot remove cause this sweet smell. All forms of this condition can result in sweet-smelling earwax and urine, which is how the condition got its name. The form your baby has depends on how well these enzymes work in their body. There are different types of maple syrup urine disease: classic, intermediate, intermittent, thiamine-response, and unclassified. Leucine, isoleucine, valine, and other related substances then build up in their body and can be toxic. As a result, babies with maple syrup urine disease have trouble breaking down branched-chain amino acids. Either the body does not make enough enzyme or does not produce the enzyme correctly. These enzymes do not work properly in babies with maple syrup urine disease. The branched-chain amino acids are called leucine, isoleucine, and valine. Your body then uses those amino acids to make other proteins that it needs to function.Ĭertain enzymes break down a specific type of amino acid called branched-chain amino acids. Your body breaks down the protein you eat into parts called amino acids. Maple syrup urine disease is an inherited (genetic) condition that prevents the body from processing proteins correctly. The gene has at least 80 kbp.Increased leucine, isoleucine, and/or other branched-chain amino acids What is Maple syrup urine disease Genomic DNA from lymphoblastoid cell lines derived from normal and five MSUD patients, in whom E1 beta was not detected by immunoblot analysis, gave the same restriction maps on Southern blot analysis. The structures and functions of mammalian alpha-ketoacid dehydrogenase complexes are apparently highly conserved.
A search for protein homology revealed that the primary structure of human BCKDH-E1 beta was similar to the bovine BCKDH-E1 beta and to the E1 beta subunit of human pyruvate dehydrogenase complex, in all regions. The subunit is synthesized as the precursor with a leader sequence of 50 amino acids and is processed at the NH2 terminus. Comparison of the amino acid sequence predicted from the nucleotide sequence of the cDNA insert of the clone with the NH2-terminal amino acid sequence of the purified mature bovine BCKDH-E1 beta subunit showed that the cDNA insert encodes for a 342-amino acid subunit with a Mr = 37,585. Nucleotide sequence analysis revealed that the isolated cDNA clone (lambda hBE1 beta-1) contained a 5'-untranslated sequence of four nucleotides, the translated sequence of 1,176 nucleotides and the 3'-untranslated sequence of 169 nucleotides. In an attempt to elucidate the molecular basis of MSUD, we isolated and characterized a 1.35 kbp cDNA clone encoding the entire precursor of the E1 beta subunit of BCKDH complex from a human placental cDNA library. A defect in the E1 beta subunit of the branched chain alpha-ketoacid dehydrogenase (BCKDH) complex is one cause of maple syrup urine disease (MSUD).