Introduction
MCAD deficiency is an inherited condition that interferes with the breakdown of certain fats, thereby impairing energy production in the body. This disorder affects metabolism and can result in serious health issues if left untreated. Hypoglycemia, or low blood sugar levels, can also occur, irrespective of blood sugar levels, and can lead to coma, liver disease, exhaustion, and other severe complications. Metabolic crises can be triggered by common ailments, high fever, stomach problems, or prolonged fasting, which makes it crucial to prevent and treat the condition early on.
MCAD deficiency is a lifelong ailment that presents at birth. In the United States, newborn screening typically includes testing for MCAD deficiency, and many other countries follow suit. Early diagnosis and treatment can effectively manage MCAD deficiency through dietary and lifestyle changes.
What Are the Symptoms?
MCAD deficiency is typically detected in infancy or early childhood, although in uncommon instances, the condition may go undiagnosed until adulthood. The symptoms of MCAD deficiency may differ from person to person and may include the following:
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Vomiting.
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Lack or low levels of energy.
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Weakness.
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Low blood sugar levels.
A metabolic crisis may be triggered by several factors, such as:
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Prolonged fasting.
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Skipping meals.
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Common infections.
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High fever.
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Persistent stomach and digestive issues that result in vomiting and diarrhea.
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Intense physical activity.
What Are the Causes?
Insufficient levels of the MCAD enzyme in the body can hinder the breakdown of medium-chain fatty acids into energy, resulting in decreased energy levels and low blood sugar. Furthermore, the accumulation of fatty acids in body tissues can lead to damage.
MCAD deficiency is caused by a genetic mutation in the ACADM gene, which is inherited in an autosomal recessive pattern from both parents. This implies that each parent carries one mutated and one unmutated gene without experiencing any symptoms of the condition. An individual with MCAD deficiency has two copies of the mutated gene, one from each parent.
Inheriting only one mutated gene does not cause MCAD deficiency, but it makes the individual a carrier who can pass on the mutated gene to their offspring. However, the condition will only develop in the child if they inherit a mutated gene from their other parent.
How to Diagnose It?
MCAD deficiency is typically diagnosed through a two-step process that involves newborn screening and genetic testing.
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Newborn screening is performed in numerous countries, including all states in the United States, shortly after birth, wherein a small amount of blood is drawn from the baby's heel and examined for abnormalities. If the screening levels deviate from the normal range, further testing is recommended.
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Genetic testing can identify the specific gene mutation responsible for MCAD deficiency. This test typically involves collecting a sample of blood, saliva, cheek cells, or skin tissue, which is then analyzed in a laboratory. It may also be suggested to test family members for the mutation. Genetic counseling is available to assist with understanding the testing process and the implications of the test results.
The diagnosis and treatment for MCAD deficiency may include a metabolic specialist and a registered dietitian. Lab tests are conducted to detect any metabolic issues that may affect the body's energy production process. By identifying such problems, potential complications can be prevented or treated.
How to Treat MCAD Deficiency?
Early detection of MCAD deficiency through newborn screening enables prompt treatment and prevention of complications before any symptoms arise. Upon receiving a diagnosis, the condition can be successfully managed by implementing an appropriate diet and necessary lifestyle adjustments.
The primary objective of managing MCAD deficiency is to prevent metabolic issues that may result in low blood sugar. This can be achieved by:
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Providing frequent feedings with an adequate intake of complex carbohydrates for infants.
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Ensuring that children and adults consume an adequate amount of complex carbohydrates at regular intervals through meals and snacks.
The doctor can recommend other treatment options, such as:
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Limit Fasting: The safe duration of fasting, that is, going without food, may depend on various factors such as age and recommendations from the healthcare provider. For instance, for healthy infants in the first four months of life, the fasting time should not exceed two to three hours. The fasting duration may be increased gradually up to 12 hours by the age of one year. Children and adults should not fast for more than 12 hours.
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Prevent Hypoglycemia: To prevent hypoglycemia or low blood sugar, the following recommendations are usually advised:
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Abstain from fasting longer than the duration suggested by the healthcare team.
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Have regular meals and snacks with sufficient calories from complex carbohydrates, such as brown rice, bread, cereal, and pasta, to meet energy needs.
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Select foods that are high in complex carbohydrates and low in fat.
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Increase calorie intake by consuming additional complex carbohydrates during periods of illness, stress, heightened activity, or before going to bed.
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Restrict alcohol consumption.
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Treat Hypoglycemia: Consult with the healthcare provider to create an emergency plan in case one experiences symptoms of low blood sugar. Emergency strategies may involve:
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Consuming simple carbohydrates, such as glucose tablets or sweetened drinks like juice, which are not labeled as "diet.
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Seeking immediate medical attention if a person is unable to eat, or if the person is experiencing diarrhea or vomiting as an intravenous (IV) line for extra glucose and additional treatment may be required in such cases.
What Are the Complications?
MCAD deficiency can cause a range of complications, including:
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Hypoglycemia (Low Blood Sugar): This is the most common complication of MCAD deficiency. Hypoglycemia can lead to seizures, coma, or even death if left untreated.
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Metabolic Crisis: This is a sudden and severe episode of metabolic disturbance that can be caused by fasting, illness, or stress. A metabolic crisis can lead to seizures, coma, or even death if left untreated.
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Liver Problems: MCAD deficiency can cause liver damage, scarring, and even liver failure in some cases.
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Brain Damage: Severe or repeated metabolic crises can cause brain damage and intellectual disability.
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Sudden Death: MCAD deficiency can cause sudden death in some cases, especially if not diagnosed and treated early.
Conclusion:
MCAD deficiency is a genetic condition that can lead to a range of complications if left untreated. Early diagnosis through newborn screening and genetic testing is crucial for effective management through dietary and lifestyle modifications. The primary objective of managing MCAD deficiency is to prevent metabolic issues that can result in low blood sugar and to treat hypoglycemia through emergency strategies. It is important to work closely with healthcare professionals to prevent and treat the condition before any severe complications arise.
