Disorder Category

An other newborn disorder



Deficiency of galactose-1-phosphate uridylyltransferase (GALT)

Tested By

Semiquantitative, fluormetric GALT enzyme assay; false positives may result from specimen exposure to excessive heat; transfusion prior to specimen collection can result in a false negative screen.



Classic galactosemia

Duarte galactosemia

Galactose-1-phosphate uridyl-transferase deficiency disease

Galactokinase (GALK) deficiency disease

UDP-galactose-4-epimerase (GALE) deficiency disease


271.1, Galactosemia


Galactose is found in many foods and is produced when lactose is split by lactase into glucose and galactose. Three enzymes are involved in the metabolism of galactose into uridine diphosphate (UDP)-glucose and, ultimately, to carbon dioxide. Mutations of each of these genes can result in galactosemia:
  • Galactose-1-phosphate uridyl-transferase (GALT) deficiency results in Classic Galactosemia, where homozygotes have less than 5% enzyme activity. Duarte variant galactosemia, with between 10% and 25% activity, results from the compound heterozygote state with a GALT mutation and a Duarte allele.
  • Galactokinase 1 (GALK1) deficiency may cause cataracts and pseudotumor cerebri. These individuals have normal GALT enzyme activity.
  • UDP-galactose-4-epimerase (GALE) deficiency can cause a benign form, in which the deficiency is found only in red blood cells and no symptoms result, and a severe form, in which the deficiency affects most tissues resulting in symptoms similar to classic galactosemia. These individuals have normal GALT enzyme activity.

Symptoms of galactosemia are the result of inadequate energy production (due to lack of conversion to glucose) and accumulation of galactose and its metabolites (specifically galactose-1-phosphate). Accumulation of galactitol, the product of an accessory metabolic pathway, can result in cataracts and pseudotumor cerebri.


Classic galactosemia occurs in about 1 in 30,000 live births; Duarte variant occurs in about 1 in 16,000.


Autosomal recessive

Prenatal Testing

DNA testing possible by amniocentesis or chorionic villus sampling (CVS) if both disease causing mutations of an affected family member have been identified. GALT enzyme activity is also possible.

Other Testing

Genetic testing is possible for at-risk family members if both disease causing mutations of an affected family member have been identified. Carrier testing by measuring GALT enzyme activity for at-risk family members is also possible.

Clinical Characteristics

For classic galactosemia, symptoms develop shortly after starting to ingest milk or other lactose containing foods. With treatment, good health may be expected. Even with therapy, some patients with classic (G/G) galactosemia can have speech defects, poor intellectual function, neurologic deficits (predominantly extrapyramidal findings with ataxia), and ovarian failure with primary amenorrhea or early menopause. Without treatment, hepatic and neurologic injury and increased risk of sepsis may lead to death.

Initial signs/symptoms may include:
  • poor feeding
  • vomiting
  • diarrhea
  • jaundice
  • bleeding diasthesis
  • lethargy
  • abdominal distention with hepatomegaly
  • increased risk of sepsis with gram negative organisms

If not treated promptly, patients may experience:
  • progressive liver failure
  • cataract
  • brain damage

Follow-up Testing after Positive Screen

Patients with a positive screening test (GALT activity level < or = 2.0 U/gHb) or who are symptomatic should be on a lactose/galactose free diet until the galactose-1-phosphate uridyltransferase enzyme level and the galactosemia DNA panel has been completed. Patients with a positive screening test with a GALT activity level >2.0 do not need dietary change. If the galactose-1-phosphate uridyltransferase and the Utah galactosemia DNA panel is consistent with classical galactosemia (GG genotype with low activity level) dietary restriction of galactose should continue. All other genotypes, including Duarte galactosemia (DG), do not require dietary restriction. In DG, the galactose-1-phosphate level may be elevated in the first year of life, but no deficits occur.

Primary Care Management

Upon Notification of the + Screen

  • Contact the family and evaluate the infant for related symptoms;
  • Provide emergency treatment/referral for symptoms of poor feeding, lethargy, jaundice, vomiting, bulging fontanel;
  • Discontinue breast or cow milk formula feeding, start feeding with Prosobee or Isomil soy formulas;
  • To confirm the diagnosis, work with the following service(s): see all Newborn Screening Programs services providers (3) in our database;
  • For evaluation and ongoing collaborative management, consult the following service(s): Pediatric Medical Genetics , (801-213-3599); See also Services below;

If the Diagnosis is Confirmed

  • Educate the family regarding signs, symptoms, and the need for urgent care when the infant becomes ill;
  • Assist in implementing and maintaining rigid dietary exclusion of lactose and galactose;
  • Monitor for developmental delays, speech delay, and, in females, ovarian failure;
  • For those identified after irreversible consequences, assist in management, particularly with developmental and educational interventions.

Specialty Care Collaboration

Initial consultation with the following service(s): Pediatric Medical Genetics , (801-213-3599); See also Services below. Ongoing collaboration if the child is affected. Genetic counseling for the family.


Information & Support

The Medical Home Portal's Galactosemia provides detailed information about diagnosis and management of galactosemia.

For Professionals

ACT Sheet for Classic Galactosemia (ACMG) (PDF Document 348 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

ACT Sheet for Primary or Secondary Hypergalactosemia (ACMG) (PDF Document 345 KB)
Contains short-term recommendations for clinical follow-up of the newborn who has screened positive; American College of Medical Genetics.

Newborn Screening ACT Sheets & Confirmatory Algorithms (ACMG)
ACTion (ACT) Sheets and algorithms for responding to positive newborn screening test results, membership required; American College of Medical Genetics.

Galactosemia (GeneReviews)
Excellent review by Louis Elsas, MD including clinical description, differential, management, genetic counseling, molecular genetics, and a bibliography; sponsored by the National Institutes of Health.

Resources for Galactosemia (NLM)
Comprehensive compilation of links to information, articles, research, case studies, genetics, and more; National Library of Medicine and the Genetic Alliance.

Galactosemia Information (UDOH)
Detailed newsletter and family education pages; Utah Newborn Screening Program, Utah Department of Health.

Genetics in Primary Care Institute (AAP)
The goal of this site is to increase collaboration in the care of children with known or suspected genetic disorders. Includes health supervision guidelines and other useful resources; a collaboration among the Health Resources & Services Administration, the Maternal and Child Health Bureau, and the American Academy of Pediatrics.

For Parents and Patients

Galactosemia (Genetics Home Reference)
Excellent, detailed review of condition for patients and families; sponsored by the U.S. National Library of Medicine. (PGC)
Information on the condition, special diets, conferences, and more; Parents of Galactosemic Children, Inc.

Galactosemia Parent Info Sheet (Nebraska Newborn Screening Program) (PDF Document 28 KB)
Single-page information sheet for parents whose child has a positive screening test; Nebraska Dept. of Health and Human Services.

Galactosemia Tutorial for Parents (English and Spanish)
Tutorials on congenital conditions; Patient Education Institute, Iowa Department of Health's Center for Congenital and Inherited Disorders.

Patient Education

What is Galactosemia? (GSLC)
An overview of the genetics of galactosemia; Genetic Science Learning Center at the University of Utah.


Genetics-related clinical services throughout the world can be found through Genetics Clinic Directory (GeneTests).

Newborn Screening Programs

See all Newborn Screening Programs services providers (3) in our database.

Pediatric Genetics

See all Pediatric Genetics services providers (5) in our database.

For other services related to this condition, browse our Services categories or search our database.

Helpful Articles

PubMed search for galactosemia and neonatal screening, last 5 years.

Freer DE, Ficicioglu C, Finegold D.
Newborn screening for galactosemia: a review of 5 years of data and audit of a revised reporting approach.
Clin Chem. 2010;56(3):437-44. PubMed abstract


Author: Nicola Longo, MD, PhD - 3/2007
Reviewing Author: Kimberly Hart, MS, LCGC - 7/2012
Compiled and edited by: Alfred Romeo, RN, PhD - 3/2007
Content Last Updated: 7/2012