What is Maltose Deficiency? Causes, Symptoms, and Treatments Explained

According to research, maltase activity can be significantly reduced in nearly all cases of congenital sucrase-isomaltase deficiency (CSID). This condition, known as maltose deficiency, impairs the body's ability to properly digest the sugar maltose, leading to uncomfortable gastrointestinal symptoms.

Quick Summary

An overview of maltose deficiency, a condition where the body cannot properly break down the sugar maltose. It covers the underlying causes, such as genetic disorders like CSID and other acquired issues, along with the resulting digestive symptoms and management strategies.

Key Points

• Maltase Enzyme Deficiency: The core of maltose deficiency is the body's inability to produce or use the maltase enzyme, which is essential for breaking down maltose.

• Genetic Cause (CSID): The most common inherited cause is Congenital Sucrase-Isomaltase Deficiency (CSID), resulting from mutations in the SI gene that disrupt enzyme function.

• Acquired Factors: Secondary maltose deficiency can be caused by intestinal damage from infections, inflammatory bowel disease, or severe malnutrition.

• Gastrointestinal Symptoms: Common symptoms include abdominal pain, bloating, excessive gas, and diarrhea, which are triggered by the bacterial fermentation of undigested maltose.

• Pompe Disease Distinction: Acid maltase deficiency, or Pompe disease, is a separate, more severe genetic condition affecting muscle glycogen storage, not the intestinal digestion of maltose.

• Management is Dietary: The primary treatment involves restricting or avoiding maltose-containing foods, such as starches found in grains.

What Is Maltose Deficiency?

Maltose deficiency refers to a condition where the small intestine lacks the necessary enzyme, maltase, to break down the disaccharide maltose into two simple glucose molecules. Maltose is a sugar naturally created during the digestion of starches found in grains, pastas, and potatoes. When this breakdown fails, the undigested maltose travels to the large intestine, where it is fermented by bacteria, causing a range of uncomfortable digestive issues.

This deficiency is primarily seen in the broader context of other disaccharidase deficiencies, such as congenital sucrase-isomaltase deficiency (CSID), where multiple carbohydrate-digesting enzymes are affected. It's crucial to understand that there are different types of maltase enzymes, and a deficiency can also refer to a rarer, more severe condition known as acid maltase deficiency (Pompe disease), which is a glycogen storage disease affecting muscle tissue.

Causes of Maltose Deficiency

Maltose deficiency can be categorized into two main types: congenital and acquired. The causes differ significantly between these forms, affecting the onset and severity of symptoms.

Congenital Sucrase-Isomaltase Deficiency (CSID)

This is the most common genetic cause of maltose deficiency. It is an inherited, autosomal recessive disorder caused by mutations in the SI gene, which provides instructions for making the sucrase-isomaltase enzyme. This enzyme complex is responsible for digesting both sucrose and a significant portion of maltose. In individuals with CSID, the sucrase-isomaltase enzyme is either dysfunctional or completely absent, leading to improper breakdown of these sugars.

Acquired (Secondary) Maltase Deficiency

This type occurs when the intestinal lining is damaged, leading to a temporary or long-term reduction in enzyme activity. Common causes include:

• Intestinal infections: Viral gastroenteritis or parasitic infections like giardiasis can temporarily damage the intestinal brush border where maltase is located.
• Other conditions: Inflammatory bowel diseases like Crohn's disease, celiac disease, or bacterial overgrowth in the small intestine (SIBO) can cause damage to the intestinal villi, leading to reduced enzyme function.
• Malnutrition: Severe malnutrition can lead to atrophy of the small bowel, which may also cause a secondary deficiency.

Acid Maltase Deficiency (Pompe Disease)

This is a distinct, much more severe genetic disorder that is often referred to when discussing maltase deficiency, although it affects a different form of the enzyme. It is a lysosomal storage disease caused by a defect in the gene for the acid alpha-glucosidase (acid maltase) enzyme. It causes glycogen to build up in nearly all types of cells, especially in muscle tissue, leading to progressive muscle weakness.

Key Symptoms of Maltose Intolerance

The symptoms of maltose deficiency, or more broadly, CSID, typically appear in infancy when starches and fruits containing maltose are introduced into the diet. For adult-onset cases, the symptoms can often be mistaken for other digestive conditions like irritable bowel syndrome (IBS).

• Abdominal pain and cramping
• Persistent watery or acidic diarrhea
• Bloating and excessive gas
• Nausea and occasional vomiting
• Failure to thrive and weight loss in infants and children
• Diaper rash, often severe due to acidic stools
• Malnutrition and slow growth in children

Diagnosis and Management Strategies

Diagnosing maltose deficiency involves a combination of tests, typically starting with an evaluation of symptoms and dietary history. The gold standard for confirming CSID is a small intestinal biopsy to measure disaccharidase enzyme levels directly. Less invasive options, like hydrogen breath tests, can also be used to detect carbohydrate malabsorption.

Treatment Options

Management of maltose deficiency centers on dietary adjustments and, for CSID, enzyme replacement therapy. There is no cure for the congenital form, so management is lifelong.

1. Dietary Restriction: Limiting or avoiding maltose-containing foods is the primary treatment. This includes starches found in grains, breads, pastas, and potatoes. The level of restriction depends on individual tolerance, which may improve with age for some individuals with CSID.
2. Enzyme Replacement Therapy: For CSID, enzyme replacement therapy is available for sucrose digestion, but it does not treat maltose deficiency. For the distinct acid maltase deficiency (Pompe disease), enzyme replacement therapy is a successful treatment.
3. Nutritional Support: A nutritionist can help create a balanced diet plan to ensure adequate nutrition despite the necessary restrictions. For infants, special formulas may be required.

Comparison of Maltose Deficiency Types

Feature	Congenital Maltose Deficiency (as part of CSID)	Acid Maltase Deficiency (Pompe Disease)
Cause	Genetic mutation in the SI gene affecting sucrase-isomaltase enzyme function.	Genetic mutation in the GAA gene affecting lysosomal acid alpha-glucosidase.
Mechanism	Inability to break down maltose in the small intestine's brush border.	Lysosomal accumulation of glycogen, particularly in muscle tissue.
Primary Symptoms	Gastrointestinal issues: diarrhea, bloating, pain, and failure to thrive.	Progressive muscle weakness, respiratory insufficiency, and cardiac involvement.
Onset	Usually in infancy, upon introduction of starches and sugars.	Can vary from infantile-onset (severe) to later childhood or adult-onset (milder).
Treatment	Primarily dietary restriction; enzyme replacement available only for sucrose.	Enzyme replacement therapy specifically targets the acid maltase defect.

Conclusion

Maltose deficiency is a carbohydrate malabsorption disorder primarily caused by genetic mutations affecting the sucrase-isomaltase enzyme, known as Congenital Sucrase-Isomaltase Deficiency (CSID). The inability to properly digest maltose and other carbohydrates leads to uncomfortable symptoms such as diarrhea, bloating, and abdominal pain. Effective management focuses on dietary restriction of maltose and associated starches, which can significantly improve quality of life. While a distinct condition called acid maltase deficiency (Pompe disease) also exists, it is a much more severe genetic disorder with different treatment protocols. A proper diagnosis from a healthcare professional is crucial for determining the correct management strategy.

For more detailed information on managing dietary restrictions for disaccharidase deficiencies, you can consult resources like the IFFGD website.

Frequently Asked Questions

What is the difference between maltose intolerance and maltose deficiency?

Maltose deficiency refers to the underlying problem—the lack of the maltase enzyme. Maltose intolerance describes the resulting symptoms, such as bloating and diarrhea, that occur after consuming foods containing maltose.

How is maltose deficiency diagnosed?

Diagnosis typically involves a small intestinal biopsy to directly measure disaccharidase enzyme levels, including maltase. Hydrogen breath tests can also be used as a less invasive way to check for carbohydrate malabsorption.

Which foods should be avoided with maltose deficiency?

Individuals should limit or avoid foods high in maltose and starches, including grains, breads, pasta, and some processed foods. A nutritionist can provide a personalized dietary plan based on individual tolerance.

Can maltose deficiency be cured?

The congenital form of maltose deficiency (CSID) is a lifelong genetic condition and cannot be cured. Acquired deficiencies, however, may resolve if the underlying cause, such as an intestinal infection, is treated.

What is the treatment for Congenital Sucrase-Isomaltase Deficiency (CSID)?

Treatment for CSID includes dietary modifications to limit sucrose and maltose intake. For sucrose digestion, an enzyme replacement therapy called sacrosidase (Sucraid®) is available, but it does not aid in maltose digestion.

Can infants have maltose deficiency?

Yes, congenital maltose deficiency typically becomes apparent in infants when they are weaned and begin consuming foods containing starches and fruits. Symptoms can include severe diarrhea and failure to thrive.

Is maltose deficiency the same as Pompe disease?

No, while Pompe disease is sometimes called acid maltase deficiency, it is a very different and more severe genetic disorder affecting muscle glycogen storage. Intestinal maltose deficiency primarily causes digestive issues.