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Unit Code 80337:
Galactose-1-Phosphate (Gal-1-P), Erythrocytes

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Useful For

Monitoring dietary therapy of patients with galactosemia due to

galactose-1-phosphate uridyltransferase deficiency or uridine

diphosphate (UDP) galactose-4-epimerase deficiency.

Clinical Information

Galactose-1-phosphate (Gal-1-P) accumulates in the erythrocytes of

patients with a deficiency of galactose-1-phosphate uridyltransferase

(GALT: classic galactosemia and its variants) or uridine diphosphate

(UDP) galactose-4-epimerase. The clinical presentation of classic

galactosemia is characterized by failure to thrive, vomiting, liver

disease, cataracts, and developmental delay. These symptoms

develop in the newborn period once a lactose-containing diet

(e.g., human and cow's milk) is introduced (lactose is a disaccharide

that is metabolized to galactose and glucose). Galactosemia is

treated by restriction of galactose from the diet, which allows for fast

recovery from the acute symptoms and a good prognosis. The

concentration of Gal-1-P in erythrocytes is the most sensitive

index of  dietary control.

Reference Values

Non-galactosemic:  5-49 ug/g of hemoglobin

Galactosemic on galactose restricted diet:  80-125 ug/g of hemoglobin

Galactosemic on unrestricted diet:  >125 ug/g of hemoglobin

Interpretation

The concentration of Gal-1-P is provided along with reference

ranges for non galactosemic probands as well as galactosemic

patients. The goal of treatment of a galactosemic patient is to keep the

Gal-1-P levels below 125 ug/g of hemoglobin.

Cautions

Not a screening test for galactosemia

Clinical Reference

1.   Gitzelmann R:  Estimation of Galactose-1-Phosphate in erythrocytes:

     A rapid and simple enymatic method. Clin Chim Acta  1969;26:313-316

 

2.   Elsas LJ:  Galactosemia. GeneClinics:  Medical

      Genetics Knowledge Base, University of Washington, Seattle.

      Retrieved1999 November 30. Available from URL:

      http://www.geneclinics.org/profiles/galactosemia/

 

3.   Holton JB, Walter JH, Tyfield LA:  Galactosemia. In The Metabolic

      and Molecular Bases of Inherited Disease. 8th edition. Edited by

      CR Scriver, AL Beaudet, D Valle, et al. New York, McGraw-Hill,

      2001, pp 1553-1587

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