Genetics. PCR. Lactose Metabolism (Determination of lactase deficiency)

Genetic study of lactose metabolism (PCR) — is a highly accurate molecular biological analysis that allows you to detect a hereditary predisposition to primary lactase deficiency. This is a condition in which the body's production of the lactase enzyme, which is necessary for the breakdown of milk sugar (lactose), decreases with age. The study is carried out by analyzing the regulatory region MCM6 gene (which controls the LCT gene, which is responsible for lactase synthesis).

Since this is a genetic analysis, it the result does not change throughout life, so it is enough to take the study only once.

Investigated indicators and interpretation of results (Genotypes)

The result of the analysis is the detection of one of three possible genetic polymorphisms (genotypes) in the C(-13910)T marker of the MCM6 gene:

1. Genotype C/C (homozygous for the wild-type allele)

   • What does it mean: Primary lactase deficiency (adult hypolactasia) is genetically determined. With age, the activity of the lactase enzyme significantly decreases or stops.

   • Clinical manifestations: High risk of dairy intolerance. Consumption of unfermented milk leads to severe discomfort (bloating, pain, diarrhea). The patient is advised to follow a lactose-free diet.

2. Genotype C/T (heterozygote)

   • What does it mean: A variant of the norm. The lactase enzyme is produced in sufficient quantities to digest moderate portions of lactose.

   • Clinical manifestations: Milk is well tolerated, however, against the background of stress, intestinal infections, or inflammatory diseases of the gastrointestinal tract, temporary (secondary) lactase deficiency may develop.

3. Genotype T/T (homozygote for the mutant allele)

   • What does it mean: Absolutely normal. The activity of the lactase enzyme remains at a high level throughout life.

   • Clinical manifestations: Excellent tolerance of dairy products. If a patient has digestive problems after consuming milk, their cause should be sought elsewhere (for example, allergy to cow's milk protein, dysbacteriosis, etc.).

Indications for appointment

• Discomfort in the gastrointestinal tract after consuming milk and dairy products (flatulence, cramps, bloating, diarrhea, nausea).

• Differential diagnosis of lactase deficiency and other gastrointestinal diseases (irritable bowel syndrome, Crohn's disease, celiac disease).

• Assessing the risk of developing osteoporosis (since lactose intolerance often leads to calcium deficiency due to avoidance of dairy products).

• Drawing up an individual nutrition plan.

• Comprehensive examination for chronic dermatitis or unexplained allergic reactions.

Preparation for the study

• If the biomaterial is venous blood: It is taken strictly on an empty stomach (last meal 8-12 hours before the analysis). You can drink plain water.

• If the biomaterial is a buccal scraping (swab from the inner surface of the cheek): 2 hours before the sample is taken, you should not eat, drink, brush your teeth, smoke, or chew gum. Before the procedure, rinse your mouth with clean water.

Important notes

Genetic testing results are not a definitive diagnosis. A final diagnosis and dietary recommendations should be made by a gastroenterologist, internist, pediatrician, or dietitian based on a comprehensive assessment of clinical symptoms and medical history.