What is it?

Maple Syrup Urine Disease (MSUD) is a disease that affects how the body breaks down the 3 amino acids; leucine, isoleucine, and valine.  Therefore the body has too many amino acids in the blood.  This leads to a quick degeneration of brain cells.  The genes cannot break down the amino acids.  Specifically the dihydrolipoamide dehydrogenase gene (DLD).  MSUD is a substitution (missense) mutation that effects the DLD gene. 
Symptoms of MSUD include loss of appetite, fussion, and sweet smelling urine (how it got its name).  If MSUD continues to go untreated, it can result in seizures, going into a coma, mental retardation, and even death.  There is a treatment out there to prevent all of these symptoms.  When babies are first dignosed with the diease, they are given an injection as well as a MSUD formula supplemented with Enfamil or Similac (protein based formulas).  Then for the remainder of their lives, MSUD patients must follow a strict, limited dietary protein diet. 
People with MSUD look just like normal people.  Look at the picture.  See the kids?  See a difference?

How can one get MSUD?  Why my child?  Genetics

MSDU is based on genetics, so why one child may get it while another may not, is based on the parents' genes.  In order to get MSUD, both parents must contain a defective copy of the gene to be passed onto the child.  A child has a 25% chance of having the disease and a 50% chance of being a carrier.  If only one of the parents has one of the defective genes (a carrier), the child cannot get it. 

What is DNA really?

 DNA stands for deoxyribonucleic acid.  It is a major componant of chromosomes (structures that carry genetic infomation).  Cells and living things use DNA to pass heredity traits from parents to childeren.  DNA is only a part of living things.  DNA cannot be found in a rock or a TV set.
DNA is in the shape of a double helix, which looks like a twisted ladder.  Its backbone consists of 2 sugar-phosphate strips that holds bands of 4 bases.  The 4 bases are Adenine (A), Thymine (T), Cytosine(C), and Guanine(G).  They bond together in orders, but A always matches with T, and C with G.  At least 1,000 base pairs make a gene, and there are 20,000-25,000 genes in the human body.  The gene that effects MSUD, DLD, contains 37058 base pairs.
DNA has a major role in the central dogma.  The central dogma is the transcription of DNA to RNA to proteins. 


Mutations occur from a error in DNA copying, or from DNA damage from enironmental sources.  Only mutaions that occur in the reproductive cells can be passed on.  They can result in disease, different hair or eye color, or even add a second toe to your foot.
There are 3 different types of mutations; Substitution, Insertion, and Deletion.  Substitution has 3 different types within itself; missense, nonsence, and silent.  Missense results in a new amino acid, nonsense results in a stop codon, and silent does no chang to the protein.  Insertion and Deletion both result in an incomplete or non-funtional protein.
Maple Syrup Urine Disease is cause by a mutation in the dihydrolipoamide dehydrogenase (DLD) gene. 
Mutations often effect the outside appearence, the part we see.  Through translation and transcription, protein synthesis determains what your features will look like.  For example, it determains weither a person has, curly or straight, blond, red, or brown hair.  It is responsible for making a persons features

Fun Facts!

  • MSUD was first noticed in 1954
  • MSUD results from the DLD gene and because the DLD gene is located on chromosome 7, it effects males and females at the same rate.
  • MSUD has no greater chance of effecting a perticular ethnic group from another.