The Impact of Carnitine and CPT Deficiency on Metabolism
Background
Long chain fatty acids are a major source of energy in humans, particularly for the heart and skeletal muscles under aerobic conditions. Individuals with carnitine or carnitine palmitoyltransferase (CPT) deficiency struggle to metabolize long chain fatty acids. This deficiency can lead to muscle weakness and hypoketosis in adults, while neonates often experience arrhythmias that can be fatal. Carnitine, an amino acid essential for transporting long chain fatty acids into the mitochondria for metabolism, is primarily obtained through diet. Most carnitine is found in voluntary and cardiac muscle tissues.
The Case
The patient in question is a 2-day-old newborn with normal bodyweight but appearing "listless." Lab results showed significantly low levels of free carnitine, while total carnitine levels fell within the normal range. An EKG revealed multiple arrhythmias. Patients with CPT II deficiency commonly develop hypoketosis.
Question:
Patients with CPT II deficiency often develop hypoketosis. Hypoketosis is simply defined as the abnormally low levels of ketones in the blood. Which statement accurately describes why CPT II deficiency can result in this condition?
Final answer:
CPT II deficiency can result in hypoketosis because it impairs the metabolism of long chain fatty acids, leading to a decrease in the production of ketones.
Explanation:
CPT II deficiency affects the metabolism of long chain fatty acids by causing a deficiency in the enzyme carnitine palmitoyltransferase II (CPT II). This enzyme is responsible for transporting long chain fatty acids into the mitochondria for metabolism. Without adequate CPT II, the body struggles to break down and utilize these fatty acids for energy. As a result, the body may rely more on alternative energy sources like glucose, leading to a decrease in the production of ketones.
Ketones are byproducts of fat metabolism, and their levels in the blood can indicate the body's ability to metabolize fats. With CPT II deficiency, the reduced production of ketones can lead to hypoketosis, characterized by abnormally low levels of ketones in the blood.