Variant forms of the disorder may become apparent only later in infancy or childhood, with typically less severe symptoms that may only appear during times of fasting, stress or illness, but still involve mental and physical problems if left untreated.Sub-divisions of MSUD:
Classic MSUD
Intermediate MSUD
Intermittent MSUD
Thiamine-responsive MSUDGenerally, majority of patients will be classified into one of these four categories but some patients affected by MSUD do not fit the criteria for the listed sub-divisions and will be deemed unclassified MSUD. Prevention
There are no methods for preventing the manifestation of the pathology of MSUD in infants with two defective copies of the BCKD gene. However, genetic counselors may consult with couples to screen for the disease via DNA testing. DNA testing is also available to identify the disease in an unborn child in the womb. Treatment
Monitoring
Keeping MSUD under control requires careful monitoring of blood chemistry, both at home and in a hospital setting. DNPH or specialised dipsticks may be used to test the patients urine for ketones (a sign of metabolic decompensation), when metabolic stress is likely or suspected. Fingerstick tests are performed regularly and sent to a laboratory to determine blood levels of leucine, isoleucine, and valine. Regular metabolic consultations, including blood-draws for full nutritional analysis, are recommended; especially during puberty and periods of rapid growth. MSUD management also involves a specially tailored metabolic formula, a modified diet, and lifestyle precautions such as avoiding fatigue and infections, as well as consuming regular, sufficient calories in proportion to physical stress and exertion.
They will also still pass one mutated copy of the gene on to each of their biological children. As a major surgery the transplant procedure itself also carries standard risks, although the odds of its success are greatly elevated when the only indication for it is an inborn error of metabolism. In absence of a liver transplant, the MSUD diet must be adhered to strictly and permanently. However, in both treatment scenarios, with proper management, those affected are able to live healthy, normal lives without experiencing the severe neurological damage associated with the disease. Pregnancy
Control of metabolism is vital during pregnancy of women with MSUD. To prevent detrimental abnormalities in development of the embryo or fetus, dietary adjustments should be made and plasma amino acid concentrations of the mother should be observed carefully and frequently. Amino acid deficiency can be detected through fetal growth, making it essential to monitor development closely. Prognosis
If left untreated, MSUD will lead to death due to central neurological function failure and respiratory failure. Early detection, diet low in branched-chain amino acids, and close monitoring of blood chemistry can lead to a good prognosis with little or no abnormal developments. Average intellectual development is below that of the general population and the severity of the deficit is a related to the time the condition remained undiagnosed and the effectiveness of dietary control including during metabolic crises. Epidemiology
Maple syrup urine disease (MSUD) is a rare, inherited metabolic disorder.