What is the Difference Between Galactosemia and Galactokinase Deficiency

The key difference between galactosemia and galactokinase deficiency is that galactosemia occurs due to a deficiency of galactose-1-phosphate uridyltransferase, while galactokinase deficiency occurs due to a deficiency of galactokinase enzyme.

Galactosemia and galactokinase deficiency are two inherited metabolic disorders of galactose metabolism. Both of these disorders are due to the deficiency of two specific enzymes. Both of these disorders usually occur with the accumulation of galactose. Moreover, these disorders can be treated through diet regulation and respective surgeries.

CONTENTS

1. Overview and Key Difference
2. What is Galactosemia 
3. What is Galactokinase Deficiency
4. Similarities – Galactosemia and Galactokinase Deficiency
5. Galactosemia vs Galactokinase Deficiency in Tabular Form
6. Summary – Galactosemia vs Galactokinase Deficiency

What is Galactosemia?

Galactosemia is an inherited metabolic disorder of galactose metabolism caused due to a deficiency of an enzyme called galactose-1-phosphate uridyltransferase. It is also known as classic galactosemia. Severe manifestations of it are typically present during early infancy. Galactosemia is an autosomal recessive metabolic disorder that can cause liver disease if it is not treated properly. In this condition, galactose-1-phosphate uridyltransferase activity is reduced or absent, which is due to inheriting a mutated copy of the GALT gene from both parents. Moreover, galactosemia leads to the accumulation of the precursors, galactose, galactitol, and Gal-1-P (galactose 1-phosphate). The signs and symptoms of galactosemia may include failure to thrive, liver damage, bleeding, infections, hyperammonemia, sepsis, shock, osmotic swelling, cataracts, developmental delay, developmental verbal dyspraxia, motor abnormalities, and ovarian failure in women.

Diagnosis of galactosemia is made through newborn screening, enzyme assays, blood tests (galactose measurement), and genetic tests. Furthermore, treatment options for galactosemia may include dietary restriction (galactose-free diet), supplementation with calcium and vitamin D, surgery (cataract), and physical, psychological, and speech therapy.

What is Galactokinase Deficiency?

Galactokinase deficiency is an inherited metabolic disorder of galactose metabolism caused due to a deficiency of an enzyme called galactokinase enzyme. Unlike galactosemia, it is normally present in less severe manifestations in early infancy. This is an autosomal recessive metabolic disorder that is characterized by the accumulation of galactose and galactitol. Galactokinase deficiency is caused by the inherited mutation of the GALK gene located on chromosome 17. The signs and symptoms of galactokinase deficiency include elevation of galactose in blood and urine, cataract, pseudotumor cerebri, cognitive impairment, deafness, a small head, small gonad (testicles and ovaries), and slower growth in height and weight.

Moreover, galactokinase deficiency can be diagnosed through laboratory blood and urine test, eye examination, and imaging tests like CT scans, MRIs, and lumber punctures. Furthermore, treatment options for galactokinase deficiency include a lactose and a galactose-restricted diet, surgery for cataracts, physical and speech therapies, and genetic counselling.

What are the Similarities Between Galactosemia and Galactokinase Deficiency?

• Galactosemia and galactokinase deficiency are two inherited metabolic disorders of galactose metabolism.
• Both of these disorders are autosomal recessive disorders.
• They are due to the deficiency of two specific enzymes.
• Both of these disorders usually present with the accumulation of galactose.
• They can be diagnosed through laboratory tests like blood and urine tests.
• These are treated through diet regulation and respective surgeries.

What is the Difference Between Galactosemia and Galactokinase Deficiency?

Galactosemia is an inherited metabolic disorder of galactose metabolism caused due to deficiency of galactose-1-phosphate uridyltransferase, while galactokinase deficiency is an inherited metabolic disorder of galactose metabolism caused due to a deficiency of galactokinase enzyme. Thus, this is the key difference between galactosemia and galactokinase deficiency. Furthermore, galactosemia is normally present with severe manifestations in early infancy, while galactokinase deficiency is normally present with less severe manifestations in early infancy.

The below infographic presents the differences between galactosemia and galactokinase deficiency in tabular form for side-by-side comparison.

Summary – Galactosemia vs Galactokinase Deficiency

Galactosemia and galactokinase deficiency are two inherited metabolic disorders of galactose metabolism. Both of these disorders usually present with the accumulation of galactose in the blood. Galactosemia is caused due to a deficiency of galactose-1-phosphate uridyltransferase while galactokinase deficiency is caused due to a deficiency of the galactokinase enzyme. So, this summarizes the difference between galactosemia and galactokinase deficiency.

Reference:

1. “Galactosemia: Definition, Symptoms & Treatment.” Cleveland Clinic.
2. “Galactokinase Deficiency.” EyeWiki.

Image Courtesy:

1. “Galactosemia” By Disorders- Eyes (CC BY-SA 4.0) via Commons Wikimedia
2. “Galactose Metabolism GALT” By Canada Hky – Own work (CC0) via Commons Wikimedia