
			Screening & Prevention

Screening and Prevention Intro
Developmental Screening
Infant Social-Emotional Screening
Maternal Depression Screening
Newborn Screening
- Amino Acid Disorders
- Endocrine Disorders
  - Congenital adrenal hyperplasia
  - Congenital hypothyroidism
- Fatty Acid Oxidation Disorders
- Galactosemias
  - Galactosemia
- Hemoglobinopathies
  - Sickle cell disease
- Organic Acidemias

Galactosemia

Screening

Finding

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.

Names

Galactosemia

Classic galactosemia

Duarte galactosemia

Galactose-1-phosphate uridyl-transferase deficiency disease

Galactokinase (GALK) deficiency disease

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

Galactose is found in many foods and is produced when lactose is split by beta-galactosidase into glucose and galactose. Three enzymes are involved in the metabolism of galactose into glucose-1-phosphate and uridine diphosphate (UDP)-galactose 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 5% and 20% activity, results from the heterozygote state with a GALT mutation and a Duarte allele.
Galactokinase 1 (GALK1) deficiency may cause cataracts and pseudotumor cerebri.
UDP-galactose-4-epimerase (GALE) deficiency causes galactosemia type III, of which there are two types. In the benign form, the deficiency is found only in red blood cells and no symptoms result. In the severe form, the deficiency is found in most tissues and the symptoms are similar to classic galactosemia.

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

Prevalence

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

Inheritance

autosomal recessive

Prenatal Testing

If the GALT mutations are known, then GALT enzyme activity or molecular genetic testing is possible.

Clinical Characteristics

For classic galactosemia, symptoms develop shortly after starting to ingest milk or other lactose containing foods. With treatment, good health and normal development can be expected. 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, and
increased risk of sepsis with gram negative organisms.

If not treated promptly, patients may experience:

progressive liver failure,
cataracts, and
brain damage.

Follow-up on positive screening test

All patients with a positive screening test should be on a lactose/galactose free diet until the test is confirmed by galactose 1-phosphate uridyltransferase electrophoresis and galactose 1-phosphate uridyl transferase quantitative testing.

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 powdered soy formula;
To confirm the diagnosis, work with the following service(s): Utah Newborn Screening Program, (801-584-8256); See also Services below;
For evaluation and ongoing collaborative management, consult the following service(s): Metabolic Clinic, (801-585-2457); 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 develomental 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 Management

Initial consultation and ongoing collaboration, particularly for dietary management. Genetic counseling for the family.

Resources

Links

For Professionals

Galactosemia Newsletter, Utah Newborn Screening Program (pdf 304kb)
Eight pages with details on screening, diagnosis, genetics, and management of galactosemia.

Galactosemia review, GeneTests.org
Excellent review by Louis Elsas, MD including clinical description, differential, management, genetic counseling, molecular genetics, and a bibliography.

Galactosemia, Iowa Dept. of Health
A 3-page overview of galactosemia from the Iowa Dept. of Health's web site.

ACT Sheet for Galactosemia from ACMG (pdf 88kb)
Developed by the American College of Medical Genetics (ACMG), includes recommended responses to positive newborn screening test results, diagnostic evaluation, clinical expectations, and sources of additional information. See the ACMG ACT Sheets and Confirmatory Algorithms (link elsewhere on this page) for more info and sheets on other conditions.

ACMG ACT Sheets and Confirmatory Algorithms
The American College of Medical Genetics (ACMG) has developed ACTion (ACT) Sheets and algorithms for responding to positive newborn screening test results. This page contains a table with links to all of the ACT Sheets and related algorithms.

Galactosemia Emergency Protocol
A protocol for management of the patient with a positive screen for galactosemia, from the New England Consortium of Metabolic Programs.

For Parents

Galactosemia, Genetics Home Reference
Excellent, detailed review aimed at patients and families from the National Library of Medicine's Genetics Home Reference site.

Galactosemia.org
Site sponsored by Parents of Galactosemic Children, Inc. (PGC) with information on the condition, special diets, conferences, and more.

Galactosemia, SaveBabies.org
Brief discussion with links to more information and support groups for parents from Save Babies Though Newborn Screening Foundation, Inc.

Galactosemia, parent info sheet, Nebraska Newborn Screening Program (pdf 108kb)
Single page information sheet for parents whose child has a positive screening test.

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

Helpful Articles

PubMed search for review articles on galactosemia in the last 5 years.

Authors

Reviewing Author:

Nicola Longo MD, PhD, 3/2007

Compiled and edited by:

Alfred Romeo RN, PhD, 3/2007

Content Last Updated:

3/2008

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Galactosemia

Disorder Category

Screening

Finding

Tested By

Names

ICD-9

Overview

Prevalence

Inheritance

Prenatal Testing

Clinical Characteristics

Follow-up on positive screening test

Primary care management

Upon notification of the + screen

If the diagnosis is confirmed

Specialty Care Management

Resources

Links

For Professionals

For Parents

Services

Newborn Screening Programs

Pediatric Genetics

Helpful Articles

Authors