Carnitine palmitoyl transferase II deficiency, neonatal form

Carnitine palmitoyl transferase II (CPT II) deficiency, neonatal form, is the most severe presentation of CPT II deficiency, a rare inherited disorder of long-chain fatty acid oxidation. CPT II is an enzyme located on the inner mitochondrial membrane that is essential for transporting long-chain fatty acids into the mitochondria, where they are broken down to produce energy. In the neonatal form, enzyme activity is profoundly reduced or absent, leading to a life-threatening energy crisis shortly after birth. This severe form typically presents within the first days of life with hypoketotic hypoglycemia (low blood sugar with inadequate ketone production), liver failure with hepatomegaly, cardiomyopathy (enlarged or weakened heart), cardiac arrhythmias, seizures, and respiratory distress. Affected neonates may also have renal dysgenesis (malformed kidneys), brain malformations, and facial dysmorphism. The condition affects multiple organ systems including the heart, liver, brain, kidneys, and skeletal muscle. Laboratory findings often include elevated long-chain acylcarnitines, low free carnitine levels, and elevated creatine kinase. The prognosis for the neonatal form is extremely poor, and the condition is often fatal within the first weeks to months of life despite medical intervention. Treatment is largely supportive and may include intravenous glucose to prevent hypoglycemia, avoidance of fasting, and dietary management with medium-chain triglyceride (MCT) supplementation to bypass the metabolic block. However, these measures are frequently insufficient to prevent multi-organ failure in this severe form. The neonatal form should be distinguished from the milder infantile (hepatocardiomuscular) and adult (myopathic) forms of CPT II deficiency, which have better prognoses.

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