Emergency Inherited Inborn Errors of Metabolism

Classic Galactosemia

Inborn Error of Carbohydrate Metabolism

Primary risk age: Neonates (Symptoms present within days of initiating milk feeding)

Urgency: Emergency
Typical age: Neonates (Symptoms present within days of initiating milk feeding)
Body system: Endocrine & Metabolic

Typical course: This is a lifelong genetic metabolic disorder requiring continuous daily dietary exclusion.

Reviewed against AAP · CDC · WHO · NHS guidance Last reviewed 2026-06-13

1. Summary & Pathophysiology

Inborn Error of Carbohydrate Metabolism

Pathophysiology (Development Path)

The enzyme deficiency prevents the conversion of galactose (derived from lactose in milk) to glucose. Galactose and its toxic metabolite, galactose-1-phosphate, accumulate in tissues, causing cell damage in the liver, kidneys, brain, and ocular lens.

Primary Causes & Etiology

An autosomal recessive mutation in the GALT gene on chromosome 9, leading to a deficiency of the enzyme galactose-1-phosphate uridylyltransferase.

2. Symptom Continuum

Early Onset Signs
Feeding difficulties, vomiting, diarrhea, and progressive lethargy within days of consuming breast milk or cow's milk formula.
Progressive Phase
Neonatal jaundice, hepatomegaly (enlarged liver), bleeding tendencies (due to liver damage), and poor weight gain.
Severe Indicators
E. coli sepsis (due to impaired leukocyte function from galactose accumulation), cataracts, renal tubular dysfunction (Fanconi syndrome), liver failure, and death if milk feeding continues.

3. Clinical Verification

Newborn screening showing elevated total blood galactose and reduced GALT enzyme activity. Confirmed with genetic testing.

4. Care & Elements Plan

Primary Care Treatment Plan

Immediately and permanently exclude all lactose and galactose from the diet. Switch to soy-based formula. Maintain a strict lactose-free diet throughout life.

Home Support Elements

Strictly avoid breast milk, cow's milk formulas, and dairy products. Check ingredient lists on processed foods and medications for hidden lactose.

Generic Active Ingredients (No Brands)

Calcium carbonate and Cholecalciferol (Vitamin D3) supplements to support bone health due to the restriction of dairy products.

Lists active elements only. Never administer self-designed therapies.

5. Doctor Critical Lines

Critical Thresholds: When to See a Doctor

Any newborn presenting with vomiting, jaundice, lethargy, or failure to feed after starting milk requires urgent evaluation.

6. Vaccine & Prevention

Routine Prophylaxis (Prevention)

Prenatal genetic testing for carrier parents; immediately stop breast/milk feeding in newborns suspected of metabolic disorders.

Immunization Context

No specific immunizations are associated with this carbohydrate metabolic disorder.

7. Timelines & Outlook

Active Timeline

This is a lifelong genetic metabolic disorder requiring continuous daily dietary exclusion.

Expected Prognosis

Good if milk is stopped immediately. Despite dietary compliance, children remain at risk for long-term complications like learning disabilities, speech delays, and ovarian failure in girls.

Potential Untreated Complications

Neonatal E. coli sepsis, cirrhosis, liver failure, cataracts, developmental delay, speech disorders, and premature ovarian insufficiency.

Severe

Phenylketonuria (PKU)

Inborn Error of Amino Acid Metabolism

Neonates (Screened at birth; symptoms develop over the first year if untreated)

Emergency

Addison's Disease (Adrenal Insufficiency)

Pediatric Primary Adrenal Insufficiency Syndrome

School-aged children and adolescents (rare in infants, though congenital forms exist)