3.4. Explain causes and symptoms of enzyme deficiency

This guide will help you answer 3.4. Explain causes and symptoms of enzyme deficiency.

Enzymes are vital proteins that facilitate chemical reactions in the body. These reactions are necessary for various functions, such as digestion, energy production, and repairing cells. Enzyme deficiency occurs when the body produces too little of a specific enzyme or the enzyme is dysfunctional. This can disrupt bodily processes, leading to various symptoms and health complications.

What is Enzyme Deficiency?

An enzyme deficiency means that the affected enzyme cannot effectively perform its job. Enzymes are highly specialised and work on specific substances called substrates. For example, the enzyme lactase breaks down lactose, which is the sugar found in dairy products. Without sufficient lactase, lactose cannot be digested properly, leading to issues like bloating and diarrhoea.

The causes of enzyme deficiency can vary and are often linked to genetic, medical, or environmental factors.

Common Causes of Enzyme Deficiency

1. Genetic Conditions:
Many enzyme deficiencies are inherited. Genetic mutations can lead to the lack of an enzyme or the production of a faulty enzyme. For example, phenylketonuria (PKU) is a genetic condition where the body cannot produce enough of the enzyme phenylalanine hydroxylase. This enzyme is vital for breaking down phenylalanine, an amino acid found in food. High levels of phenylalanine can harm the brain and lead to intellectual disabilities if not managed.

2. Medical Conditions: Certain health problems can decrease enzyme production or function. For instance:

• Pancreatitis, or inflammation of the pancreas, can reduce the production of enzymes like lipase, amylase, and protease, which are essential for digesting fats, carbohydrates, and proteins.
• Liver diseases such as cirrhosis can impair the production of enzymes needed for metabolism.

3. Autoimmune Disorders: Conditions like coeliac disease or Crohn’s disease can damage the gastrointestinal tract. This reduces the body’s ability to produce enzymes needed for digestion. Enzyme production may resume if the underlying condition is treated.

4. Nutritional Deficiencies: The body needs vitamins and minerals to produce enzymes. A lack of key nutrients, such as zinc or B vitamins, may lead to lower enzyme activity.

5. Ageing: As people age, the body’s ability to produce certain enzymes naturally declines. For example, older adults may produce less lactase, increasing their risk of lactose intolerance.

6. Damage to Organs: If an organ that produces enzymes is injured or diseased, enzyme production will be affected. For example, damage to the pancreas from alcohol abuse can limit digestive enzyme production.

7. Environmental Factors: Exposure to toxins, such as pesticides or heavy metals, may interfere with enzyme activity. Radiation and certain medications can also affect enzyme production.

Common Symptoms of Enzyme Deficiency

Symptoms depend on the type of enzyme that is deficient or malfunctioning. Below are examples of symptoms associated with common types of enzyme deficiencies.

1. Digestive Enzyme Deficiencies: These deficiencies affect the enzymes that break down food, such as:

• Lactase Deficiency (Lactose Intolerance): Without lactase, the body cannot digest lactose. Symptoms include abdominal pain, diarrhoea, bloating, and gas after consuming dairy products.
• Amylase Deficiency: Amylase breaks down carbohydrates. Its deficiency can lead to undigested starch in the gut, causing bloating and gastrointestinal discomfort.
• Lipase Deficiency: Lipase digests fats. Without it, undigested fats can result in greasy stools, diarrhoea, and weight loss.
• Protease Deficiency: Protease breaks down proteins. Deficiency may cause protein malabsorption, leading to fatigue, weakened immunity, and difficulty gaining weight.

2. Metabolic Enzyme Deficiencies: These deficiencies affect enzymes involved in metabolism. Examples include:

• Phenylketonuria (PKU): High levels of phenylalanine in the blood can lead to developmental delays, seizures, and behavioural problems if untreated.
• Fabry Disease: This is caused by a deficiency of the enzyme alpha-galactosidase A, leading to symptoms such as severe pain, skin rash, kidney problems, and heart disease.
• G6PD Deficiency: Glucose-6-phosphate dehydrogenase (G6PD) is involved in protecting red blood cells. Its deficiency can lead to anaemia, fatigue, and jaundice, especially after eating certain foods or taking specific medications.

3. Lysosomal Storage Disorders: Lysosomes are cellular structures that break down complex molecules. Enzyme deficiencies in lysosomes lead to the accumulation of substances, causing tissue damage. For example:

• Gaucher Disease: Caused by a deficiency of the enzyme glucocerebrosidase. Symptoms include bone pain, enlargement of the spleen and liver, and easy bruising.
• Tay-Sachs Disease: Caused by the deficiency of hexosaminidase A, leading to a progressive loss of motor and cognitive abilities.

4. Urea Cycle Disorders:
The urea cycle removes ammonia from the body. Enzymes like carbamoyl phosphate synthetase I play a role in this cycle. If there is an enzyme deficiency, ammonia accumulates, causing symptoms like confusion, vomiting, and lethargy.

Diagnosing Enzyme Deficiency

Healthcare professionals use various methods to diagnose enzyme deficiencies, including:

• Medical History and Symptoms: A doctor may ask about symptoms, dietary habits, and family history of enzyme deficiencies or genetic conditions.
• Laboratory Tests: Blood, stool, or urine tests may be carried out to assess enzyme activity levels and identify deficiencies. For example, a stool test can determine if fat digestion is incomplete, possibly indicating lipase deficiency.
• Genetic Testing: This can identify inherited conditions like PKU or Tay-Sachs disease by checking for specific gene mutations.
• Elimination Diets: Sometimes, doctors recommend removing specific foods from the diet to see if symptoms improve, such as avoiding dairy in suspected cases of lactose intolerance.

Treating Enzyme Deficiency

Treatment focuses on managing symptoms and compensating for the missing or defective enzyme. Here are some common approaches:

• Enzyme Replacement Therapy (ERT): Involves taking enzyme supplements to replace the missing enzyme. For example, pancreatic enzyme supplements can help treat pancreatic insufficiency.
• Dietary Modifications: Avoiding foods that trigger symptoms can improve quality of life. For example:
• Avoiding lactose-containing foods for lactase deficiency.
• Following a low-protein diet for PKU.
• Managing Underlying Conditions: Treating health issues like pancreatitis or coeliac disease can restore normal enzyme function.
• Medications: Some medications may help reduce symptoms. For example, lactase tablets can help individuals with lactose intolerance digest dairy.
• Specialised Care for Inherited Conditions: These may involve ongoing monitoring and support from dietitians, genetic counsellors, and specialists.

Preventing Enzyme Deficiency

Preventing some enzyme deficiencies may not be possible, especially if they are genetic. However, for those influenced by lifestyle or environmental factors, prevention may include:

• Healthy Lifestyle Choices: This includes limiting alcohol intake and maintaining a balanced diet to promote optimal organ health.
• Avoiding Toxin Exposure: Reducing contact with harmful chemicals and pollutants can support enzyme function.
• Treating Disorders Promptly: Managing conditions like diabetes or inflammatory bowel disease may reduce the risk of enzyme-related complications.

Final Thoughts

Enzyme deficiency disrupts essential bodily functions, leading to a range of symptoms and potential health issues. Causes include genetic conditions, medical problems, nutritional deficiencies, and environmental factors. Addressing an enzyme deficiency often requires a combination of dietary changes, enzyme replacement, and treating underlying conditions. Early diagnosis and treatment can significantly improve quality of life for those affected. Understanding the causes and symptoms is key to helping individuals get the support they need.