Unit

UNIT 17.5 Diagnosis of Inherited Disorders of Galactose Metabolism

  1. Carla Cuthbert,
  2. Helene Klapper,
  3. Louis Elsas

Published Online: 1 JAN 2008

DOI: 10.1002/0471142905.hg1705s56

Current Protocols in Human Genetics

Current Protocols in Human Genetics

How to Cite

Cuthbert, C., Klapper, H. and Elsas, L. 2008. Diagnosis of Inherited Disorders of Galactose Metabolism. Current Protocols in Human Genetics. 56:17.5:17.5.1–17.5.29.

Author Information

  1. Leonard Miller School of Medicine, University of Miami, Miami, Florida

Publication History

  1. Published Online: 1 JAN 2008
  2. Published Print: JAN 2008

Abstract

Galactose metabolism occurs through an evolutionarily conserved pathway in which galactose and uridine diphosphoglucose are converted to glucose-1-phosphate and uridine diphosphogalactose through the action of three sequential enzymes: galactokinase (GALK, EC 2.7.1.6), galactose-1-phosphate uridyltransferase (GALT, EC 2.7.7.12), and uridine phosphogalactose 4′-epimerase (GALE, EC 5.1.3.2). Inborn errors of galactose metabolism occur with impaired activity for each of the enzymes. Classical galactosemia is the most common and the most severe of these diseases and is caused by deficiency of the GALT enzyme, affecting from ∼1 in 10,000 to 1 in 30,000 live births. Deficiency of GALE is the rarest of the three diseases. Assays for galactitol and galactose-1-phosphate and methods for assaying enzyme activities of GALT, GALK, and GALE are provided here. Interpretation of diagnostic results for screen-positive newborns or symptomatic patients, as well as therapeutic interventions based on biochemical phenotype and molecular genotype, are also included as decision trees. Curr. Protoc. Hum. Genet. 56:17.5.1-17.5.29. © 2008 by John Wiley & Sons, Inc.

Keywords:

  • galactosemia;
  • galactose;
  • metabolism;
  • galactose-1-phosphate;
  • galactitol;
  • neonatal screening