Aldolase B gene (hereditary fructose intolerance)

The test looks for the most common changes in the ALDOB gene, which holds the blueprint for the enzyme aldolase B. The sample is EDTA blood; as a genetic test, written consent is required.

What aldolase B does in the body

Aldolase B works in the liver, kidneys and small intestine. It splits fructose-1-phosphate, the first step in breaking down fruit sugar. Fructose is found in fruit, table sugar (sucrose) and as sorbitol in many foods.

Change detected – what happens in the body?

If both gene copies are changed, hereditary fructose intolerance is present. Fructose-1-phosphate then builds up in the cells, binds phosphate and uses up energy (ATP). The liver can neither release sugar from its stores nor make new sugar – after fructose-containing food, low blood sugar, nausea, vomiting and abdominal pain occur; over time the liver and kidneys are strained. A single changed copy usually causes no symptoms.

No change – what does it mean?

Without the changes tested for, hereditary fructose intolerance is unlikely. The much more common fructose malabsorption – reduced uptake of fruit sugar in the gut – is not covered by the genetic test; the fructose breath test exists for that. Because of possible low blood sugar, the genetic test is used before a fructose breath test when an inherited form is possible.

The interpretation is given in your report.