Disease Directory Classic Galactosemia
Metabolic

Classic Galactosemia

Also known as: GALT deficiency, galactose-1-phosphate uridyltransferase deficiency, type I galactosemia

Prevalence

1-9 per 100,000 (Orphanet)

Onset

Neonatal

Type

Autosomal recessive genetic

Gene

GALT

About Classic Galactosemia

Classic galactosemia is caused by severe deficiency of galactose-1-phosphate uridyltransferase (GALT), which is essential for metabolizing galactose found in lactose (milk sugar). Newborns present with jaundice, liver failure, E. coli sepsis, and cataracts within days of milk feeding. Despite dietary galactose restriction, most patients develop long-term complications including intellectual disability, speech problems, and in females, primary ovarian insufficiency.

Common Clinical Features

Neonatal liver failure Cataracts E. coli neonatal sepsis Intellectual disability Speech apraxia Primary ovarian insufficiency Tremor

Clinical Trial Eligibility Tips

What to know before applying to Classic Galactosemia trials.

Erythrocyte GALT enzyme activity is the gold standard diagnostic test — Beutler test results should be documented

Galactose-1-phosphate level in red blood cells is the primary efficacy biomarker in dietary and drug trials

Long-term complication trials (cognitive, fertility) often enroll adults with confirmed classic galactosemia on lifelong galactose restriction

New substrate reduction and small molecule therapies are in early trials — no prior investigational therapy is typically an inclusion criterion

Patient Resources

Patient Organization

Galactosemia Foundation

Visit website ↗

Natural History Registry

Galactosemia Foundation Registry

Join registry ↗

Orphanet

European reference resource for rare diseases (ORPHA:352)

View on Orphanet ↗

NORD

National Organization for Rare Disorders

Search NORD ↗

Find recruiting Classic Galactosemia trials

Search 500,000+ studies from ClinicalTrials.gov, filtered for Classic Galactosemia. Updated daily.

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