What is the Difference Between Phenylketonuria and Galactosemia

The key difference between phenylketonuria and galactosemia is that phenylketonuria is caused due to the accumulation of an amino acid called phenylalanine in various organs of the body, while galactosemia is caused due to the accumulation of galactose related chemicals in various organs of the body.

Phenylketonuria and galactosemia are two inherited metabolic disorders. Inherited metabolic disorders refer to different types of medical conditions caused by genetic defects or mutations. Most commonly, they are inherited from both parents and interfere with the body’s metabolism. These conditions may also be called inborn errors of metabolism.

CONTENTS

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

What is Phenylketonuria?

Phenylketonuria is a rare inherited metabolic disorder. It occurs due to the accumulation of an amino acid called phenylalanine in various organs of the body. Phenylketonuria is caused by a defect in the gene (PAH) that codes the enzyme needed to break down phenylalanine. Without this enzyme, a dangerous build-up of this amino acid happens when the person eats foods that contain protein or eats aspartame (an official sweetener). This eventually leads to serious medical problems. For the rest of their lives, people with PKU (babies, children, and adults) need to follow a diet that limits phenylalanine. Moreover, babies in the United States and many other countries are screened for PKU soon after birth. Recognizing PKU the right way can help prevent health problems.

PKU signs and symptoms may be mild or severe, and they include a musty odour in the breath, neurological problems such as seizures, skin rashes, fair skin and blue eyes, abnormally small head, hyperactivity, intellectual disability, delayed development, behavioural, emotional and social problems, and psychiatric disorders. This condition can be diagnosed through family history, blood tests, and genetic testing. Furthermore, a lifetime diet with a very limited intake of protein, neutral amino acid therapy, and PKU medications such as the drug sapropterin (Kuvan) are the treatment options for PKU.

What is Galactosemia?

Galactosemia is a rare inherited metabolic disorder that occurs due to the accumulation of galactose-related chemicals in various organs of the body. It is a rare inborn error of metabolism that affects an individual‘s ability to metabolize galactose properly. Galactosemia follows the autosomal recessive mode of inheritance, and it is due to an enzyme that is responsible for adequate galactose degradation. This disorder is caused by a deficiency of an enzyme called galactose 1 phosphate uridylyl transferase (GALT) and is due to mutations in genes such as GALT, GALK1 and GALE.

The symptoms of galactosemia may include convulsions, irritability, lethargy, poor feeding, poor weight gain, yellow skin, white eyes (jaundice) and vomiting, diarrhoea, cataracts, liver damage, kidney problems, developmental disabilities, and ovaries malfunction in girls. Moreover, diagnosis of this condition can be performed through family history, blood tests, urine tests, DNA analysis, and enzyme analysis. Furthermore, the treatment option for galactosemia includes a low galactose diet. This means that milk and other foods containing lactose or galactose cannot be consumed. In addition, speech therapy, individual educational planning, and intervention, hormone replacement therapy can be useful for treating other symptoms.

What are the Similarities Between Phenylketonuria and Galactosemia?

• Phenylketonuria and galactosemia are two inherited metabolic disorders or inborn errors of metabolism.
• Both are due to inherited genetic mutations that cause enzymes decencies.
• Both follow the autosomal recessive mode of inheritance.
• They are treatable through restricting diets.

What is the Difference Between Phenylketonuria and Galactosemia?

Phenylketonuria is a rare inherited metabolic disorder caused due to the accumulation of an amino acid called phenylalanine in various organs of the body, while galactosemia is a rare inherited metabolic disorder caused due to the accumulation of galactose related chemicals in various organs of the body. Thus, this is the key difference between phenylketonuria and galactosemia. Furthermore, phenylketonuria is due to the mutation of the PAH gene, while galactosemia is due to the mutations of genes such as GALT, GALK1, and GALE.

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

Summary – Phenylketonuria vs Galactosemia

Phenylketonuria and galactosemia are two inherited metabolic disorders or inborn errors of metabolism. Phenylketonuria occurs due to the accumulation of an amino acid called phenylalanine in various organs of the body, while galactosemia occurs due to the accumulation of galactose-related chemicals in various organs of the body. So, this summarizes the difference between phenylketonuria and galactosemia.

Reference:

1. “Phenylketonuria.” NORD (National Organization for Rare Disorders).
2.“Galactosemia: Symptoms, Causes, Diagnosis, Treatment.” WebMD.

Image Courtesy:

1. “Phenylalanine metabolism” By Allen Gathman (CC BY-NC-SA 2.0) via Flickr
2. “Galactosemia” By Disorders  (CC BY-SA 4.0) via Commons Wikimedia