Summary about Disease
Carnitine palmitoyltransferase II (CPT II) deficiency is a genetic metabolic disorder that prevents the body from using certain fats for energy, particularly during periods of fasting or prolonged exercise. It affects the CPT II enzyme, which is essential for transporting fatty acids into the mitochondria (the cell's energy-producing compartments) for beta-oxidation. There are three main forms: a severe infantile form, a less severe myopathic form, and a rare neonatal form. The myopathic form is the most common.
Symptoms
Myopathic form: Muscle pain and weakness (myalgia), often triggered by exercise, fasting, or illness. Rhabdomyolysis (muscle breakdown) can occur, leading to muscle cramps, fatigue, and dark-colored urine (myoglobinuria).
Severe infantile form: Usually presents in infancy with hypoketotic hypoglycemia (low blood sugar with inappropriately low ketone levels), liver problems, seizures, cardiomyopathy (enlarged heart), and respiratory failure.
Neonatal form: Usually fatal, with symptoms presenting at birth or shortly after, including the same problems as the severe infantile form but often more severe.
Causes
CPT II deficiency is caused by mutations in the CPT2 gene. It is inherited in an autosomal recessive pattern, meaning both parents must carry a copy of the mutated gene for a child to be affected.
Medicine Used
There is no cure for CPT II deficiency, but symptoms can be managed. The primary treatment is dietary management and lifestyle modifications.
L-Carnitine Supplementation: May be beneficial in some individuals to improve carnitine availability.
Medium-chain triglyceride (MCT) oil: Supplementation.
Avoidance of prolonged fasting: Patients should eat frequent meals and snacks to prevent metabolic crises.
Glucose Administration: Intravenous glucose may be needed during metabolic crises to provide an alternative energy source.
Is Communicable
No. CPT II deficiency is a genetic disorder and is not contagious or communicable.
Precautions
Dietary Management: Adhere strictly to a diet that is low in long-chain fats and high in carbohydrates. Work with a registered dietitian specializing in metabolic disorders.
Avoid Fasting: Regular meals and snacks are crucial.
Avoid Strenuous Exercise: Excessive physical activity can trigger symptoms, especially in the myopathic form.
Medical Alert: Wear a medical alert bracelet or necklace indicating CPT II deficiency and carry emergency information.
Infections: Treat all infections as soon as possible.
Inform Medical Professionals: Always inform healthcare providers about the CPT II deficiency before any medical procedure or treatment.
How long does an outbreak last?
The duration of symptoms can vary. Muscle pain and weakness may last for a few hours to several days following exercise or fasting. Rhabdomyolysis can last longer and requires medical management. Infantile onset cases require constant medical management.
How is it diagnosed?
Newborn Screening: Some states include CPT II deficiency in their newborn screening programs, which uses a blood spot test to identify affected infants early.
Blood Tests: Analysis of acylcarnitine levels in the blood can suggest CPT II deficiency. Elevated levels of long-chain acylcarnitines are often seen.
Enzyme Assay: A blood test or muscle biopsy can measure the activity of the CPT II enzyme.
Genetic Testing: DNA sequencing of the CPT2 gene can identify mutations that cause CPT II deficiency.
Urine Tests: Assess for myoglobinuria which indicates muscle breakdown
Timeline of Symptoms
Severe Infantile Form: Symptoms appear within the first few days or months of life.
Myopathic Form: Symptoms typically appear in childhood or adolescence, but can occur later in adulthood. Onset is usually triggered by exercise, fasting, or illness.
Neonatal Form: Symptoms present at birth or shortly after.
Important Considerations
Genetic Counseling: Families with a history of CPT II deficiency should seek genetic counseling to understand the risk of having an affected child.
Emergency Planning: Develop an emergency plan with a healthcare provider to manage metabolic crises. This may include instructions for intravenous glucose administration.
Long-term Management: Regular monitoring by a metabolic specialist is crucial to manage the condition effectively and prevent complications.
Pregnancy: Women with CPT II deficiency require close monitoring during pregnancy.
Vaccinations: Routine vaccinations are recommended to prevent infections, which can trigger metabolic crises.