Disease of maple syrup (leucinosis)

Description:

The disease of urine of maple syrup (English MSUD, Russian BMKS) (other name of a disease - a ketoaciduria with a branched chain or a leucinosis) is the autosomal and recessive disbolism caused by disturbance of metabolism of amino acids with a branched chain. This frustration is one of types of organic acidemias. The name, a disease received from a specific sweet smell of urine at sick babies.

Etiologies of maple syrup (leucinosis):

The disease of urine of maple syrup affects about 1 person from 180000 newborns. At spread of this disease the effect of the founder is of great importance. The disease meets among children of Amishes, Mennonites and Jews more often.

BMKS cause mutations in the following genes:
  
- BCKDHA (OMIM - 608348);
- BCKDHB (OMIM - 248611);
- DBT (OMIM - 248610);
- MG (OMIM - 238331).

These four genes code the proteins controlling activity of a complex of alpha ketonic acids of a dehydrogenase with a branched chain (BCKDC). This complex as it was already told, plays importance when splitting amino acids of a leucine, isoleucine and valine which are present at many food stuffs (especially in those which are rich with protein, for example milk, meat and eggs). Mutations in any of these genes reduce activity or in general deactivate activity of a fermental complex, breaking, thus, normal metabolism of an isoleucine, leucine and valine. As a result of these processes of amino acid and by-products of their disintegration collect in an organism. And as the high level of these substances - is toxic for a brain and other bodies, their accumulation result serious medical problems.

This frustration has the autosomal and recessive nature of inheritance. It means that the defective gene is located on an autosome and two of its copies (on one from each parent) were inherited by the child. The child's parents with autosomal and recessive frustration are, as a rule, carriers of one copy of a defective gene, but, any symptoms of a disease at them, usually, is not shown.

Symptoms of a disease of maple syrup (leucinosis):

The disease is characterized by existence of a sweet smell of urine at small children (a smell similar to a smell of maple syrup). At the birth children have no visible symptoms of a disease. However, if frustration not to treat, then patients have serious injuries of a brain which can lead to the death of the struck child.

The main symptoms of a disease of maple syrup (which are shown almost right after the birth):
  
-  small appetite,
-  vomiting,
-  dehydration,
-  slackness,
-  hypotonia,
-  spasms,
-  hypoglycemia,
-  ketoacidosis,
-  opisthotonos,
-  pancreatitis,
-  coma
-  and various neurologic disturbances.

Classification.
  
The disease of maple syrup is divided into several types which are allocated according to signs and symptoms, or according to the genetic reasons. The classical type which is shown right after the birth is considered the most common and severe form of a disease. Other forms can arise a bit later and, as a rule, also less heavy is easier than manifestation of these types. However, in the absence of due treatment of BMKS in all cases leads to emergence of heavy mental and physical deviations.

There are several types of a disease:

  - classical (heavy) BMKS;
  - intermediate BMKS;
  - periodic BMKS;
  - thiamin sensitive BMKS;
  - BMKS with deficit of E3 and lactoacidosis (accumulation of lactic acid).

Treatment of a disease of maple syrup (leucinosis):

Maintenance of BMKS under control demands careful monitoring of chemical composition of blood and includes both special diets, and frequent carrying out the corresponding analyses. Food of sick BMKS has to contain the minimum level of amino acids of a leucine, isoleucine and valine - for avoidance of damages of a nervous system. But, considering that these three amino acids necessary for appropriate performance of metabolic functions of an organism (at all people), are used today the special proteinaceous drugs containing substitutes of amino acids which allow to keep the level of amino acids at the safe level without doing at the same time harm to an organism. These drugs (some of which are already used, and some only pass the corresponding clinical tests) allow sick BMKS to eat normally without prejudice to health.
Usually sick BMKS demand consultation of the nutritionist, they have to adhere to a specific diet constantly. However, at observance of all requirements and control, people sick BMKS can lead healthy, normal life without those neurologic deviations which can arise during a disease.