GALE

Galactose Epimerase Deficiency

Clinical Characteristics
Ocular Features: 

At least some patients have childhood cataracts which may be unilateral.  Direct assay of GALE activity in lenses shows a significant decrease in at least some patients.

Systemic Features: 

This rare disorder of galactose metabolism has an especially wide range of expression.  Some patients seem to have little or no clinical disease whereas others are severely affected.   Early cases were found to have epimerase deficiency only in circulating red blood cells while other cells seemed to have normal levels of the enzyme.  Some of these patients have virtually no symptoms.  Later, cases were found that resembled classic galactosemia (230400) in presentation and even responded to galactose restriction diets. Current thought favors the hypothesis that the same gene defect is responsible for the entire continuum of clinical disease.  Red blood cells have elevated levels of galactose-1-phosphate.

 

Genetics

This is an autosomal recessive disorder resulting from mutations in the GALE gene (1p36-p35.

Another disorder of galactose metabolism causing early onset cataracts is galactokinase deficiency (230200) caused by mutations in GALK1.

Pedigree: 
Autosomal recessive
Treatment
Treatment Options: 

A galactose-restricted diet is beneficial.  Since these patients are unable to utilize the endogenous pathway of synthesis for UDP-galactose they are dependent on exogenous galactose and therefore some galactose is required in the diet.

References
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