Glucose-galactose malabsorption deficiency is a rare, inherited disorder characterized by impaired absorption of glucose and galactose in the small intestine. This condition is associated with a deficiency of the specific transport protein SGLT1 (Sodium-Glucose Co-Transporter 1), which is responsible for the absorption of these monosaccharides from the intestinal lumen. In the absence or deficiency of this protein, consumption of foods containing glucose and galactose can lead to severe clinical manifestations, including diarrhea, dehydration, and hypoglycemic states. The disease may manifest itself in early childhood after the introduction of carbohydrates into the diet, especially lactase (in milk) and carbohydrates contained in starch.
History of the disease and interesting historical facts
Glucose-galactose malabsorption deficiency was first described in detail in the medical literature in the 1970s, although cases of the disease may have been observed much earlier, remaining undiagnosed. A number of studies conducted at this time allowed us to establish the genetic nature of the disease, as well as its pathophysiological mechanisms. Interestingly, until the 1990s, the diagnosis was often made based on clinical signs, and only after the introduction of molecular genetic diagnostic methods were doctors able to more accurately identify the hereditary factors and mutations that cause this disease. It is known that the SGLT1 defect has arisen independently in several population groups, which may indicate convergent evolution leading to similar mutations in different populations.
Epidemiology
The prevalence of glucose-galactose malabsorption deficiency is extremely low, with the latest data suggesting that it occurs in approximately 1 in 100,000 live births. However, the prevalence may vary by geographic region and ethnic group. It is likely that the prevalence is significantly higher in certain highly inbred populations. For example, higher rates may be seen in Arab countries or highly related populations, while the disease remains rare in the general population.
Genetic predisposition to this disease
Glucose-galactose malabsorption deficiency is inherited in an autosomal recessive manner, meaning that two mutant copies of the SLC5A1 gene are required for clinical symptoms to occur. The SLC5A1 gene is located on chromosome 22 and codes for the SGLT1 protein. Mutations in this gene can vary, and more than 30 different mutations have been identified that can affect the function of the protein and reduce its ability to transport glucose and galactose. Research suggests that some mutations have also been associated with changes in the structural configuration of the protein, making it ineffective at transporting sugars.
Risk factors for the development of this disease
The following factors may be associated with an increased risk of developing glucose-galactose malabsorption deficiency:
- Heredity: A family history of the disease may indicate potential risks in newborns.
- Genetic mutations: presence of known mutations in the SLC5A1 gene.
- Lack of prenatal diagnosis: lack of genetic testing for prospective parents in predisposed families.
- Age: the disease most often manifests itself in the first year of life.
Diagnosis of this disease
Diagnosis of glucose-galactose malabsorption deficiency includes:
— Main symptoms: mainly acute diarrhea, vomiting, weight loss, dehydration.
— Laboratory tests: blood glucose and galactose levels, urine carbohydrate excretion test.
— Radiological examinations: X-rays and ultrasounds can be used to rule out other diseases.
— Other types of diagnostics: molecular genetic methods (sequencing of the SLC5A1 gene).
— Differential diagnosis: carbohydrate diarrhea and malabsorption syndromes (eg, celiac disease).
Treatment
Treatment of glucose-galactose malabsorption deficiency requires a comprehensive approach. Includes:
— General treatment: strict diet excluding glucose and galactose.
— Pharmacological treatment: the use of sucrose or fructose, which may be more easily absorbed by patients with this pathology.
- Surgical treatment: In rare cases, surgical correction may be required to treat complications such as intestinal obstruction.
— Other treatments: supportive therapy to restore electrolyte balance and prevent dehydration.
List of medications used to treat this disease
Drugs used to manage the symptoms of the disease and its consequences include:
- Sucrose (as a carbohydrate source)
- Electrolyte solutions (to restore water-electrolyte balance)
- Fructose (as an alternative source of sugars)
Disease monitoring
Monitoring of patients with glucose-galactose malabsorption deficiency includes:
— Control stages: regular visits to the doctor to assess the patient’s condition and adjust diet and treatment.
— Prognosis: When the diet is followed, the prognosis for children is generally good, but complications such as growth retardation or nutritional deficiencies are possible.
— Complications: May include persistent diarrhea, electrolyte deficiencies, and growth problems.
Age-related features of the disease
This disease manifests itself mainly in childhood and requires special attention when introducing foods containing glucose and galactose into the diet. In newborns and infants, the disease may manifest itself suddenly, while older children may adapt to the diet over a period of time, but with a chronic lack of carbohydrates, symptoms of malnutrition may appear.
Questions and Answers
- What are the main symptoms of glucose-galactose malabsorption deficiency? The main symptoms include diarrhea, vomiting, weight loss and dehydration.
- How is this disease diagnosed? Diagnosis includes laboratory tests, molecular genetic tests and assessment of clinical symptoms.
- How to treat this disease? Treatment consists of strict exclusion of glucose and galactose from the diet, as well as the use of alternative carbohydrates.
- What is the likelihood of complications developing? The prognosis is generally good if the prescribed diet is followed, however, without treatment, complications and growth retardation are possible.
- Is it possible to diagnose the disease in adults? The disease usually manifests itself in childhood, but may be diagnosed later if symptoms of malabsorption are present.
Finally, Dr. Oleg Korzhikov advises parents with a family history of glucose-galactose malabsorption to undergo genetic testing. He emphasizes the importance of careful monitoring of children’s diets and suggests using alternative carbohydrate sources, such as fructose and sucrose, which may be safe and digestible for such patients. “Monitor your child’s condition, and if you notice any unusual symptoms, do not delay a visit to the doctor,” the doctor adds.
