CPT deficiency is a short term used for carnitine palmitoyl transferase deficiency. It is a very rare enzyme deficiency disease that produces weakness in muscles, enlargement of liver, malfunctioning liver and variety of other symptoms. Carnitine is a substance that is usually available in the body from the food that you eat.
There are two types of CPT enzymes; CPT1 and CPT2. Deficiency can develop with any of the two types.
CPT 1 deficiency: CPT1 enzyme work is to carry the fatty acids into the cells. In CPT1 deficiency the fatty acids cannot penetrate to the cells because of lack of this enzyme.
CPT2 deficiency: The main function of CPT2 enzyme is to make the cells utilize the fat once it enters into the cell with the help of CPT1 enzyme. CPT2 deficiency is further divided into 3 subtypes; Myopathic type, severe infantile type and lethal neonatal variety. Myopathic form is milder than the other two. Most lethal is lethal neonatal form where the infant does not live more than few months due to this deficiency.
Causes:
The cause of CPT deficiency occurs due to abnormality (mutation) either in CPT 1 gene or CPT 2 gene. Problem with this gene mutation does not allow CPT 1 or CPT 2 enzyme work properly. CPT deficiency is an inherited disease. This means the disease runs in family. The disease is extremely rare and for this to happen, faulty genes must come from both the parents. Mutation in any of these genes can extremely reduce the activity of carnitine palmitoyl transferase function. Without these enzymes the carnitine that you get from food cannot be utilized. The long chain fatty acids cannot reach mitochondria of the cells to be converted into energy. In normal circumstances when you fast, the stored fat in the body is utilized as a source of energy. But because the fat cannot make its way into the cell due to CPT 1 or 2 deficiencies, it is not used. This may lead to hypoketotic hypoglycemia. The circulating fatty acids build up in the liver, heart, and other organs causing mild to severe damage. This condition can be present equally in men and women.
Symptoms of CPT Deficiency:
Deficiency of CPT symptoms can develop during infancy or it may appear during adulthood depending on the type of deficiency. The symptoms tend to worsen especially when you are fasting or performing strenuous exercise or during viral illness, exposure to extreme temperature, stress etc. Symptoms include as follows:
- It can lead to hypoglycemia or low blood sugar.
- Liver enlargement
- Recurrent episodes of pain in muscles
- Weakness in muscles caused due to breakdown of the muscle tissues
- Low level of ketones. Ketone is byproduct that is released after breakdown of fat that is used for energy production. However, because fat is not utilized, the byproduct ketone is less.
- Damage to nervous system
- Coma and death
- Seizures in lethal neonatal type.
Diagnosis:
- CPT deficiency is diagnosed by a physician, usually a neurologist or a geneticist. Before the diagnosis the physician takes medical history and examines the patient physically. Family history is very important as this condition is inherited. Certain tests are recommended to confirm the diagnosis. This tests include;
- Blood test: It helps to check the level of carnitine in the blood. Liver enzymes may be elevated due to liver failure and enlargement.
- Urine test: Helps to detect ketone bodies in urine and myoglobin passed in urine due to breakdown of myoglobin.
- Genetic test: This test confirms the diagnosis of the deficiency.
- Sonography of abdomen and Echocardiogram helps to analyze the heart and liver function.
Treatment:
The main treatment of CPT deficiency is dietary management. Since fat remains unutilized due to deficiency of CPT enzyme deficiency, it is obvious to eat less fatty and protein containing food. If you eat more fat food it will not be utilized and thus may get stored in heart and liver where excess built of fat can cause severe damage to these vital organs. The best way to reduce any symptoms is to increase the intake of carbohydrate containing diet. Patient has to eat frequently food that contains carbohydrate. This will also prevent hypoglycemia. Ample amount of carbohydrate will prevent the body using fats as a fuel as an energy source. Besides making dietary changes, patient suffering from CPT deficiency must also prevent triggers such as fasting or skipping meals, stress, too much exercising, exposure to extreme cold or hot temperature.