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Diagnosis of galactosemia
Last reviewed: 04.07.2025
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Laboratory diagnostics
Galactosemia type I
The main methods for confirming the diagnosis of galactosemia I are biochemical: determination of the concentration of galactose and galactose-1-phosphate in the blood and/or measurement of the activity of the enzyme galactose-1-phosphate uridyltransferase in erythrocytes.
In families with an adverse heredity, prenatal DNA diagnostics may be performed if the proband's genotype has been established.
Galactosemia type II
Typically, the disease is diagnosed during mass screening for galactosemia. The diagnosis is confirmed by determining the enzyme activity in red blood cells or fibroblasts. DNA diagnostics are also possible.
Galactosemia type III
Biochemical methods for confirming the diagnosis include determining the enzyme activity in red blood cells and the content of galactose and galactose-1-phosphate. DNA diagnostics are also possible.
Interpretation of results
Galactosemia type I
Difficulties in interpreting metabolic changes are associated with the fact that liver damage of other etiologies (both hereditary and non-hereditary) may increase the level of galactose in the blood. False-positive tests have been described for tyrosinemia, congenital biliary atresia, neonatal hepatitis and many other diseases. Determination of enzyme activity is a more specific and reliable test, but its results are affected by the storage and transportation mode of the samples. False-positive results can also be obtained with glucose-6-phosphate dehydrogenase deficiency. In addition, some polymorphic variants of the gene and their combinations with mutant alleles can distort the results of biochemical diagnostics.
Differential diagnostics
Galactosemia type II
Differential diagnosis is carried out with other forms of galactosemia and hereditary forms of cataracts.
Galactosemia type III
Differential diagnosis: other forms of galactosemia.
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