Galactosemia

Test

• Biochemical assay detecting galactose uridyl transferase and galactose-one-phosphate (the Beutler test).  Heat and humidity degrade the transferase, yielding false positives.
• Hill test: fluorometric assay for galactose, used with Beutler, only positive after milk ingestion
• Paigen E. coli phage test: more reliable, also identifies other galactose disorders
• Confirmatory test
• Urine for non-reducing substances (+++ galatosemia, + galactokinase or epimerase deficiency, ++ in Vit. C), if negative, likely problem with fructose metabolism
• serum galactose and gal-1-phosphate, erythrocyte gal-1-phosphate uridyltransferase (by electrophoresis)

Genetics

• Autosomal recessive
• 1:60,000 to 1:80,000

Pathology

• A cellular deficiency in one of the enzymes needed to convert galactose to glucose.  Galactose-1-phosphate uridyl transferase (GALT) deficiency is the defect in the severe form of the disease

Diagnosis

• Symptoms occurs within the first two weeks of life: jaundice, vomiting, lethargy, hepatosplenomegaly, cataracts, and failure to thrive may proceed to severe morbidity from liver failure, sepsis, or bleeding. Death may occur.
• E. coli sepsis may be a presenting sign.
• Physical findings include cerebral palsy, ataxia, seizures, mental retardation, cataracts, and liver disease.

Treatment

• A galactose-free diet for life.  Normal IQs are possible if treatment is started before 10 days of age, but learning and speech problems are still common.  Ovarian failure has occurred in the majority of treated females.

Acknowledgment

Also see other Inborn Errors of Metabolism.
 

Genetics

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