Insufficient intestinal disaccharidases
Hereditary defects in bowel disaccharidases system manifest persistent gastrointestinal disorders and dystrophy, which is caused by a violation of digestion and absorption of disaccharides in the intestinal mucosa.In 1958, P. Durand found in the child malnutrition with a low activity of the enzyme that breaks down milk sugar, while determined a significant amount of lactose in the urine of the patient.We should talk about the autosomal dominant type of inheritance.
lactase deficiency is more common other forms disaccharidase deficiency, therefore attracting the most attention, since milk and dairy products are major in nutrition of many nations, especially in childhood.If lactase deficiency is relatively rare (2-30%) in Europe, in some parts of Africa and Asia - more than 90% of the total population.only a few population-based studies of the spread of disease carried out in our country.
Already in the first reports about ethnic differences in the frequency of lactase deficiency occur assumptions abou
been suggested the existence of other genetic mechanisms of lactase deficiency.Congenital deficiency of the enzyme that breaks down milk sugar explain gene mutation responsible for the synthesis of lactase, whereby the enzyme is either not synthesized or formed by its inactive form.In adults lactase deficiency is assumed gene mutation, resulting in a structurally normal enzyme, but the process is very slow, what is the reason, perhaps, hormonal disturbances.This view considers lactase deficiency as a mutation, a defect in certain genes, and ability to break down lactase - like species of human ability.In addition to the genetic theory of lactase deficiency, received, despite some shortcomings, the universal recognition, expressed the hypothesis, considering the disease as a result of intestinal diseases, as well as the assumption that the enzyme deficiency is the result of the braking effect of certain foods on the activity of lactase in the intestinal mucosa.In humans, eating milk, the level of the enzyme in the intestinal mucosa is high, and among people who use it in small quantities or not at all eats dairy products, common deficiency.However, all attempts to cause an increased number of researchers lactase (the enzyme) using lactose or milk food were unsuccessful.
Saharazno-izomaltaznaya failure - a variant of hereditary intolerance to disaccharides, due to decreased activity of enzymes such as maltase and isomaltase, as well as lack of intestinal mucosa invertase enzyme.It revealed the genetic nature of the disease.Some authors speak of autosomal dominant inheritance, while others argue that the inheritance of sucrase deficiency is an autosomal recessive, especially in cases of blood marriages.Homozygous individuals for life remain an intolerance sucrose and heterozygous enzyme deficiency may be asymptomatic, or saharaznaya failure occurs only in childhood.Boys and girls suffer equally often.
case of insufficient enzymes such as sucrase, isomaltase and maltase, are quite rare.There is a birth defect of the enzyme sucrase, whereby sucrose is not split into glucose and fructose.Maltase and isomaltase deficiency is usually combined with other disaccharidases deficit.In severe intolerance to starch but maltase and isomaltase deficiency, should bear in mind the chronic pancreatic insufficiency, as well as an extremely rare condition congenital absence of pancreatic amylase.With maltasie and izomaltaznym deficit can be combined lactase deficiency, especially acquired.Combined saharazny, izomaltazny and maltasie deficiency occurs much more frequently.Loss of function of several enzymes is the result of a single mutation or multifunctional missing enzyme, which explains the combination of metabolic defects, and some splitting of disaccharides.It is believed that the structural gene controlling the synthesis of several enzymes damaged under the influence of exposure to toxic or infectious, or one and the same factor, toxic or infectious, disables multiple enzymes.