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SLC5A1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

SLC5A1 gene

The SLC5A1 gene provides instructions for the SGLT1 protein, which is essential for the absorption of glucose and galactose from the diet in the intestines and kidneys.

Normal Function

The SLC5A1 gene provides instructions for producing a protein called sodium/glucose cotransporter protein 1 (SGLT1). This protein is found mainly in the intestinal tract and the kidneys. It spans the cell membrane and transports the sugars glucose and galactose from outside the cell to inside the cell, along with sodium and water.

In the intestines, SGLT1 is located in the microvilli of epithelial cells, where it absorbs these sugars from food. In the kidneys, SGLT1 is located in the proximal tubules, where it acts as the final step in ensuring glucose is reabsorbed into the bloodstream rather than being lost in the urine.

Health Conditions Related to Genetic Changes

Glucose-galactose malabsorption

More than 60 mutations in the SLC5A1 gene have been found to cause glucose-galactose malabsorption. This condition begins in infancy and is characterized by severe, life-threatening diarrhea, weight loss, and dehydration. Mutations impair or eliminate the function of the SGLT1 protein, preventing the absorption of glucose and galactose. These sugars accumulate in the intestinal tract, drawing water with them and causing severe dehydration. While SGLT1 is also involved in kidney glucose reabsorption, other proteins like SGLT2 can often compensate, meaning glucose in the urine (glucosuria) is usually mild or absent in these patients.

Other Names for This Gene

  • D22S675
  • Human Na+/glucose cotransporter 1 mRNA, complete cds
  • NAGT
  • SC5A1_HUMAN
  • SGLT1
  • solute carrier family 5 (sodium/glucose cotransporter), member 1
  • solute carrier family 5 (sodium/glucose transporter), member 1

Genomic Location

The SLC5A1 gene is found on chromosome 22.

Frequently Asked Questions

Severe, watery diarrhea that begins within hours of feeding, rapid weight loss, dehydration, and failure to thrive are hallmark signs. If these symptoms appear in a newborn or toddler, the clinician should order a stool osmotic gap test and consider a genetic test for SLC5A1 mutations.
The diet must exclude all free glucose and galactose. This means avoiding milk, fruit juices, honey, and foods containing lactose or sucrose. Instead, use specialized formulas or lactose‑free products, and incorporate complex carbohydrates like rice or corn starch that are absorbed without SGLT1. A registered dietitian can create a balanced meal plan that meets caloric and nutrient needs.
Glucosuria is usually mild or absent because other transporters (e.g., SGLT2) compensate in the kidneys. When present, it indicates that some glucose reabsorption still occurs, but the primary problem remains intestinal absorption. Monitoring urine glucose can help assess the severity of the transporter defect.
Sequencing of the SLC5A1 gene using next‑generation sequencing panels for inherited metabolic disorders is the standard approach. If a known pathogenic variant is identified, family members can be screened by targeted testing. Genetic counseling is recommended to discuss inheritance (autosomal recessive) and recurrence risks.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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