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Alternative name
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Galactose-1-phosphate uridyltransferase (GUT) deficiency
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About the condition
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Classical galactosaemia is a carbohydrate disorder. It is a hereditary disease that is caused by a missing enzyme needed to metabolise galactose. Galactose is a product of the digestion of lactose or milk sugar. Without treatment, galactose accumulates in the blood and causes organ toxicity.
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Inheritance
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Autosomal recessive
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| Year screening started in WA |
1980 |
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Incidence in WA
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1 in 60,000 births
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Enzyme defects
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Deficiency of the enzyme galactose-1-phosphate uridyltransferase. Galactokinase and UDP-galactose-4-epimerase deficiencies may also be detected.
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Symptoms if untreated
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Infants with classical galactosaemia are usually normal at birth; however, they soon develop jaundice and vomiting, and they fail to gain weight.
Other symptoms of the condition include:
- Liver failure and renal dysfunction
- E.coli sepsis
- Intellectual disability
- Cataracts
Infants who are diagnosed early have good long-term outlooks although some may develop problems with their speech and women may suffer from infertility.
Galactokinase deficiency only causes cataracts.
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Metabolites on bloodspot screening
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- Increased galactose and galactose-1-phosphate
- Decreased GUT enzyme activity
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Diagnostic tests
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- Blood galactose-1-phosphate and plasma galactose
- RBC GUT activity
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Treatment
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Treatment with a lactose-free diet prevents the life-threatening complications.
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Screening issues
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- The galactose metabolites are only increased if the affected baby is on milk feeds
- Where milk feeding has not been established the screening laboratory measures GUT activity instead
- The screening test should be performed before exchange transfusion
- The screening test my detect other rare forms of galactosaemia: galactokinase and epimerase deficiencies
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