Its prevalence in the United States population is approximately 1 newborn out of 180,000 live births. However, in populations where there is a higher frequency of consanguinity, such as the Mennonites in Pennsylvania or the Amish, the frequency of MSUD is significantly higher at 1 newborn out of 176 live births. In Austria, 1 newborn out of 250,000 live births inherits MSUD. It also is believed to have a higher prevalence in certain populations due in part to the founder effect since MSUD has a much higher prevalence in children of Amish, Mennonite, and Jewish descent. Research directions
Gene therapy
Gene therapy to overcome the genetic mutations that cause MSUD have already been proven safe in animals studies with MSUD. The gene therapy involves a healthy copy of the gene causing MSUD is produced and inserted into a viral vector. The adeno-associated virus vector is delivered one-time to the patient intravenously. Hepatocytes will take up vector and functional copies of the affected gene is MSUD patients will be expressed. This will allow BCAA to be broken down properly and prevent toxic build up. Phenylbutyrate therapy
Sodium phenylacetate/benzoate or sodium phenylbutyrate has been shown to reduce BCAA in a clinical trial done February 2011. Phenylbutyrate treatment reduced the blood concentration of BCAA and their corresponding BCKA in certain groups of MSUD patients and may be a possible adjunctive treatment. See also
Isovaleric acidemia
Methylmalonic acidemia
Propionic acidemia
John Menkes

References
External links

Maple syrup urine disease at NLM Genetics Home Reference
msud at NIH/UW GeneTests
Mechanism
On the molecular level, it is thought that gastroparesis can be caused by the loss of neuronal nitric oxide expression since the cells in the GI tract secrete nitric oxide. This important signaling molecule has various responsibilities in the GI tract and in muscles throughout the body. When nitric oxide levels are low, the smooth muscle and other organs may not be able to function properly. Other important components of the stomach are the interstitial cells of Cajal (ICC) which act as a pacemaker since they transduce signals from motor neurons to produce an electrical rhythm in the smooth muscle cells. Lower nitric oxide levels also correlate with loss of ICC cells, which can ultimately lead to the loss of function in the smooth muscle in the stomach, as well as in other areas of the gastrointestinal tract.Pathogenesis of symptoms in diabetic gastroparesis include:

Loss of gastric neurons containing nitric oxide synthase (NOS) is responsible for defective accommodation reflex, which leads to early satiety and postprandial fullness. Impaired electromechanical activity in the myenteric plexus is responsible for delayed gastric emptying, resulting in nausea and vomiting. Sensory neuropathy in the gastric wall may be responsible for epigastric pain. Abnormal pacemaker activity (tachybradyarrhythmia) may generate a noxious signal transmitted to the CNS to evoke nausea and vomiting. Diagnosis
Gastroparesis can be diagnosed with tests such as barium swallow X-rays, manometry, and gastric emptying scans.