Galactose Handling

Your result, the one DNA position behind it, and what the research says.

5/10 confidence.

About Galactose Handling

Lactose is a double sugar: digesting it releases glucose and galactose. Glucose is used directly, but galactose has to be converted first, and GALT does that conversion. This change is usually described as the Duarte marker, and the description is looser than it sounds. On its own the substitution is neutral: laboratory tests in cells and yeast show the enzyme works normally with it. What it does is travel alongside two different versions of the gene, one with reduced activity and one with entirely normal activity, so carrying it makes the reduced version likelier without establishing it. The change that actually lowers activity is a small deletion in the gene's control region, which this card does not read. Either way there is ample capacity for ordinary dietary galactose.

Good to know: Digesting lactose releases galactose, which needs its own conversion step. Every result here leaves ample capacity for a normal diet. The version this card marks is the ancestral form, shared with other primates.

Fun fact: The version this card marks is the original one: humans are the ones who changed, and other primates still carry the ancestral form.

Discovery: The Duarte variant of GALT was characterized through newborn screening programs from the 1960s onward.

The Variant

The single variant behind this trait

Gene: GALT

Variant (rsID): rs2070074

Location: Chr 9:34,649,445

dbSNP rs2070074

The studies

Origins, distribution and expression of the Duarte-2 (D2) allele of galactose-1-phosphate uridylyltransferase (Carney AE et al., Human molecular genetics, 2009)

Other lifestyle traits

Histamine Clearance: A change in diamine oxidase, the gut enzyme that breaks down histamine arriving in food, affecting how quickly you clear it.

Secretor Status: A change that decides whether you secrete your blood group antigens into saliva, tears and gut fluid, which shapes the bacteria your gut hosts.

Nicotine Receptor: A change in a nicotine receptor subunit, one of the strongest known influences on how much people who smoke tend to smoke.

Back to All Traits

Content updated September 2026.

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