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LCT

Lactase (phlorizin hydrolase)

Gene Number: 3938

Location: 2q21.3

Key Functions: Lactose digestion, intestinal nutrient absorption, gastrointestinal health, evolutionary adaptation


LCT (lactase) encodes the enzyme lactase–phlorizin hydrolase (LPH), which is found on the surface of cells lining the small intestine. Its primary job is to break down lactose, the main sugar in milk, into the simpler sugars glucose and galactose, which the body can absorb and use for energy. This function is especially vital during infancy, when milk is the primary source of nutrition.

SNP ID
Your Genotype
Alt Allele
Interpretation
rs4988235
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A
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rs4988235

  • AA – Lactase persistence; can digest milk as an adult (R).

  • AG – Mostly lactase persistent; ~80% can digest milk as adults (R).

  • GG – Lactase non-persistence; likely lactose intolerance in adulthood (R).

Functional effect: The A allele (-13910*T, in an enhancer within MCM6) upregulates LCT expression, maintaining lactase into adulthood; strongest evidence in Europeans (gene–environment/ancestry effects apply) (R).


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