Diagnosis of galactosemia
Last reviewed: 23.04.2024
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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-phosphaturidyl transferase in erythrocytes.
In families with burdened heredity, prenatal DNA diagnostics is possible if the genotype of the proband is established.
Galactosemia, type II
As a rule, the disease is diagnosed in a mass screening for galactosemia. The diagnosis is confirmed by determining the activity of the enzyme in erythrocytes or fibroblasts. It is also possible to conduct DNA diagnostics.
Galactosemia, type III
Biochemical methods for confirming the diagnosis include the determination of enzyme activity in blood erythrocytes and the content of galactose and galactose-1-phosphate. It is also possible to conduct DNA diagnostics.
Interpretation of results
Galactosemia type I
Difficulties in interpreting metabolic changes are due to the fact that in the defeat of the liver of another etiology (both hereditary and non-hereditary), an increase in the level of galactose in the blood is possible. False positive tests for tyrosinemia, congenital atresia of biliary tract, neonatal hepatitis and many other diseases are described. Determination of enzyme activity is a more specific and reliable test, but its results are influenced by the mode of storage and transportation of samples. Also, false positive results can be obtained with insufficiency of glucose-6-phosphate dehydrogenase. 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 performed with other forms of galactosemia and hereditary forms of cataract.
Galactosemia. Type III
Differential diagnosis: other forms of galactosemia.
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