In detail, the disease is characterized by a defect in the metabolism of branched-chain amino acids (also called BCAAs, from the English Branched Chain Amino Acids) - leucine, isoleucine and valine - resulting in a rather severe symptomatology.
The disease owes its name to the fact that one of the characteristic symptoms is the smell of the urine, very similar to that of maple syrup.
(prevalence of approximately 1 / 185,000 live births worldwide) also known as leucinosis, branched-chain ketoaciduria or branched-chain ketoacid dehydrogenase deficiency.
It is characterized by the deficiency of the branched-chain alpha-ketoacid dehydrogenase complex, a complex of multi-subunit enzymes responsible for the metabolism of branched amino acids, such as leucine, isoleucine and valine. This deficiency is due to localized mutations in the coding genes. for the subunits that make up the aforementioned enzyme Transmission is autosomal recessive.
The deficiency of the above enzymatic complex causes the patient to accumulate high quantities of branched amino acids and the corresponding keto acids; condition that can cause serious damage to the organism.
The disease manifests itself from the earliest stages of the infant's life even if, initially, the affected children appear healthy.
located on genes that code for the synthesis of the E1a, E1b and E2 subunits of the branched-chain alpha-ketoacid dehydrogenase enzyme complex (BCKADC, from the English Branched Chain Keto Acid Dehydrogenase C.omplex). More specifically, the genetic mutations responsible for the disease are found on the BCKDHA (19q13.1-q13.2), BCKDHB (6q14.1) and DBT (1p31) genes.of the child who remembers that of maple syrup (hence the name of the disease). Other symptoms of the disease are represented by:
- Sharp crying;
- Poor appetite;
- Loss of body weight;
- Metabolic crisis that can occur with:
- Lack of energy;
- Irritability;
- He retched;
- Respiratory difficulties.
- Dehydration;
- Hypotonia;
- Hypoglycemia;
- Opisthotonus;
- Convulsions;
- Delays in development;
- Progressive encephalopathy with lethargy.
Without prompt treatment, the disease can lead to central respiratory failure, coma and death.
metabolizing its proteins. In the absence of adequate treatment, coma occurs within 7-10 days and the consequences are tragic.
Maple Syrup Urine Disease Intermediate
The intermediate form of MSUD is a rare form in which the enzymatic activity of the branched-chain alpha-ketoacid dehydrogenase complex is slightly higher than the classical form and is approximately 3-8% of normal activity.The symptoms are similar to that of classic MSUD, but may be less severe and may begin later than the latter.
Intermittent Maple Syrup Urine Disease
The intermittent form of maple syrup urine disease is characterized by the late onset of symptoms, approximately around the first or second year of the child.
Although it is an asymptomatic form after birth, it can cause developmental delays during infancy. However, compared to those previously mentioned, the intermittent form is lighter and the enzymatic activity of the alpha-ketoacid dehydrogenase complex a branched chain is slightly higher, indicatively, from 8% to 15% of normal activity.
Thiamine-sensitive Maple Syrup Urine Disease
Clinically, the thiamine-sensitive form of MSUD is similar to the intermediate form and is also a rare form. It is characterized by the fact that the disease improves following the administration of certain concentrations of thiamine (or vitamin B1 which In detail, following treatment with thiamine, there is a greater food tolerance to leucine. Nevertheless, patients must still follow a restrictive diet (see chapter "Care and Treatment").
neonatal which normally involves taking a blood sample from the newborn and carrying out various analyzes.
If the baby presents symptoms after the neonatal period, the diagnosis can be made through blood tests, or through urinalysis.
If, on the other hand, there is a known family history of MSUD, then it is possible to perform an antenatal diagnosis by performing appropriate genetic tests.
intravenous insulin and lipids. In some cases, hemodialysis may also be required.Once the acute phase of the disease has been controlled, the infant should be fed milk free of BCAAs (branched chain amino acids). A diet free of BCAAs, or in any case with very low concentrations, must be strictly maintained for the entire duration of the patient's life.
Sometimes, orthotopic liver transplantation can be a useful treatment. On the other hand, it is a very delicate surgical procedure which, unfortunately, is not practicable in every patient.
Therefore, leaving out the possibility of the aforementioned transplant, the emergency treatment of the acute phase and the maintenance of a restrictive and rigorous diet associated with continuous monitoring of the patient, at the moment, represent the only therapeutic strategy for urinary disease. Maple syrup.
Maple Syrup Urine Disease Diet
The maple syrup urine disease diet is restrictive as it requires you to severely limit - in order to respect the tolerability limit of each individual - all those foods with a high protein content, such as meat, eggs and dairy products At the same time, however, the diet must guarantee the patient the intake of fundamental nutrients, such as other essential amino acids, mineral salts and vitamins.
Such a particular and so rigorous diet, of course, must be established on a strictly individual basis for each patient by a doctor who specializes in this type of metabolic pathology.
