Galactosemia

Disease Description (Causes and Symptoms)

• Definition and causes: Galactosemia is an autosomal recessive disorder caused by a genetic deficiency of enzymes involved in galactose metabolism. The main types are
  • Type 1: Galactose-1-phosphate uridyltransferase (GALT) deficiency — the most severe
  • Type 2: Galactokinase (GALK) deficiency — mainly causes cataracts
  • Type 3: Galactose epimerase (GALE) deficiency — rare, with varied clinical manifestations
• Pathophysiology: Lactose is broken down into galactose and glucose. When galactose cannot be metabolized normally, galactose and its metabolites (especially Galactose-1-phosphate) accumulate in the blood and tissues, causing cellular damage in the liver, kidneys, brain, eyes, and other organs.
• Major symptoms (neonatal period):
  • Poor feeding, vomiting, poor weight gain, diarrhea
  • Jaundice, hepatomegaly, abnormal liver function (may progress to hepatitis or cirrhosis)
  • Cataracts (develop rapidly, particularly with GALK deficiency)
  • Susceptibility to infections (e.g., Escherichia coli sepsis)
  • Neurological abnormalities (lethargy, seizures), and, over the long term, developmental delay and intellectual disability
  • In girls, premature ovarian insufficiency (affecting reproductive function)
• Diagnostic summary: Suspected through newborn screening (heel-prick blood test, Beutler test) → urine reducing substance test (Clinitest), measurement of increased blood galactose and Gal-1-P, red blood cell enzyme activity (GALT, GALK, GALE), and genetic testing for confirmation.
• Prevalence: Varies depending on the report, but is approximately 1 in 50,000–60,000 births (based on Type 1).

Treatment Methods and Precautions

• Acute phase (immediately upon suspicion)
  • Immediately stop galactose and lactose intake: Stop breastfeeding and regular formula, then switch to an alternative diet with no or extremely little galactose (e.g., lactose-free specialized formula, plant-based (soy) formula, or an elemental formula as directed by a doctor).
  • Hospital treatment for complications such as infection, hypoglycemia, and abnormal liver function (fluid and electrolyte correction, antibiotics, liver-function support, etc.).
• Long-term management
  • Restrict galactose in the diet for life (or after childhood): Restrict dairy products (including milk, butter, and whey protein) and foods containing galactose. (Dietary recommendations may vary depending on the individual type and severity, so follow a specialist’s instructions.)
  • Treatment by complication: For cataracts, ophthalmologic evaluation and surgery if necessary; early intervention for developmental delay and learning problems (rehabilitation and speech therapy); gynecologic evaluation and hormonal management for ovarian dysfunction.
  • Regular follow-up tests: Growth and development, liver function tests (LFTs), bone density, endocrine evaluation (particularly ovarian function in girls), and hearing and vision assessments.
• Education and emergency planning
  • Educate patients and caregivers about lists of foods containing galactose and how to check food labels.
  • Advise them to contact a medical facility immediately in the event of acute fever, vomiting, or reduced fluid intake (the risk of complications increases with fasting or dehydration).
• Drug therapy or enzyme replacement therapy is not standard treatment; supportive treatment for complications is the main approach.

Outpatient Visit Checklist (Suggested Items to Bring and Example Questions)

• Suggested items to bring
  • A list of currently used medications and supplements
  • Copies or records of recent test results (newborn screening results, blood tests, liver function test results, etc.)
  • Recent weight and height records (growth chart), and diet and feeding records (which formula or foods were consumed)
  • Family history (similar symptoms or genetic disorders in relatives), and a copy of genetic test results if available
• Symptoms to report first to the nurse/doctor during the outpatient visit
  • Signs of dehydration risk, such as fever, vomiting, diarrhea, or refusal to eat
  • Worsening jaundice, a tendency to bleed, decreased consciousness, or seizures
• Example questions (items to prepare and ask the doctor in advance)
  • "Which product is safe to choose for the current formula (or diet)?"
  • "What should be done first if an emergency occurs, such as vomiting or fever?"
  • "Which regular tests are needed, and how often should they be performed?"

Examples of General Questions to Ask the Doctor

• Are there any side effects or interactions with galactose involving this medication or supplement (e.g., calcium or vitamin D)?
• What is the long-term prognosis of this disorder, and which complications should be monitored most carefully?
• Which recommended checkups (vision, hearing, and intelligence testing) and schedules can help support growth and development?
• For female patients, what should be prepared in relation to fertility (premature ovarian insufficiency)?

Examples of Disease-Specific Questions

• (For caregivers of girls) What follow-up tests and timing do you recommend regarding my daughter’s reproductive potential (puberty and the possibility of pregnancy)? Are there any special recommendations for preserving ovarian function?
• (General) What is the recommended interval for ophthalmologic follow-up and what are the surgical indications for reducing the risk of cataracts or managing early cataracts?
• Is genetic testing of parents and siblings or carrier testing recommended, when should it be performed, and is prenatal or preconception counseling necessary?

(Additional information) The diagnosis and treatment plan vary depending on each patient’s type and severity of enzyme deficiency. Establish a dietary and follow-up examination plan based on accurate test results and consultation with a specialist.