1. Prevalence
1.1. rare disease
1.1.1. in U.S. disease is seen in 1 out of 180,000 births.
1.2. highest prevalence in
1.2.1. Amish
1.2.2. Mennonite
1.2.2.1. communities with higher frequency of consanguinity see MSUD in approximately 1 out of 176 births
1.2.3. Jewish
1.3. mainly seen in children directly after birth
1.4. late onset of MSUD seen in less severe cases
2. Diagnostics
2.1. Newborns screened at 1-2 days old
2.1.1. blood tests performed to obtain concentration levels of leucine and isoleucine
2.1.1.1. results are compared to concentrations of other amino acids
2.1.1.1.1. blood work determines if newborn has surplus of said amino acids.
2.2. Newborns screened at 2-3 days old
2.2.1. require urine samples due to increase in overall amino acid concentrations in body
2.2.1.1. newborn's urine is analyzed for levels of branched-chain alpha-hydroxyacids and alpha-ketoacids.
3. Treatment
3.1. no ways of preventing disease
3.1.1. genetic counseling available to help carriers determine risks.
3.2. must monitor ketone levels constantly
3.2.1. specialized dip sticks available
3.3. special individualized diet
3.3.1. must monitor intake levels of food/drinks high in
3.3.1.1. leucine
3.3.1.2. isoleucine
3.3.1.2.1. depending on severity of disease some patients require a feeding tube to receive daily nutrition.
3.3.1.3. valine
3.3.2. protein-restricted diet to decrease intake of leucine, isoleucine, and valine
3.4. high doses of thiamine
3.4.1. used as coenzyme for the breakdown of sugars and amino acids
3.4.2. over the counter drug used for many genetic disorders including MSUD.
3.5. Liver Transplantatioin
3.5.1. provides chance of permanently restoring metabolic function
3.5.2. procedure works best in young patients
4. Strauss, K. A., MD, Puffenberger, E. G., PhD, & Morton, D. H., MD. (2013). Maple Syrup Urine Disease. GeneReviews. Retrieved October 1, 2017, from Maple Syrup Urine Disease
5. Maple syrup urine disease - Genetics Home Reference. (n.d.). Retrieved October 01, 2017, from maple syrup urine disease
6. Pathogenesis
6.1. Body unable to break down certain amino acids.
6.1.1. amino acids build up in
6.1.1.1. blood
6.1.1.2. urine
6.1.1.2.1. gives off sweet aroma similar to maple syrup
6.2. Mutation in
6.2.1. BCKDHA
6.2.2. BCKDHB
6.2.3. DBT
6.2.3.1. any of 4 genes can cause MSUD
6.2.3.1.1. these four genes produce proteins that form branched-chain alpha-keto acid dehydrogenase complex
6.2.4. DLD
7. Risk Factors
7.1. Inherited disorder
7.1.1. Autosomal recessive
7.1.1.1. defected gene on autosome
7.1.1.2. parents must be carriers
7.1.1.2.1. child unaffected
7.1.1.2.2. child unaffected carrier
7.1.1.2.3. child affected
8. Signs and Symptoms
8.1. symptoms during metabolic crisis include
8.1.1. erratic behavior/mood
8.1.2. anorexia
8.1.3. anemia
8.1.4. diarrhea
8.1.5. vomiting
8.1.6. lethargy
8.1.7. ataxia
8.1.8. seizures
8.1.9. hypoglycemia
8.1.10. ketoacidosis
8.1.11. pancreatitis
8.1.12. neurological decline
8.1.13. coma
8.1.14. cerebral edema
8.1.15. sweet smelling urine