Familial apolipoprotein C-II deficiency

Familial apolipoprotein C-II (apo C-II) deficiency is a very rare inherited disorder of fat metabolism. It is also known as familial chylomicronemia due to apo C-II deficiency or hyperlipoproteinemia type Ib. In this condition, the body cannot properly break down certain fats (triglycerides) in the blood because it lacks a key protein called apolipoprotein C-II. This protein normally activates an enzyme called lipoprotein lipase, which is responsible for clearing fat particles (chylomicrons and very low-density lipoproteins) from the bloodstream. Without functioning apo C-II, triglyceride levels become extremely high, often reaching thousands of milligrams per deciliter. The hallmark symptom is recurrent episodes of acute pancreatitis, which causes severe abdominal pain and can be life-threatening. Other common signs include eruptive xanthomas (small yellowish bumps on the skin caused by fat deposits), lipemia retinalis (a milky appearance of the blood vessels in the eye), and hepatosplenomegaly (enlarged liver and spleen). The blood itself may appear milky or creamy due to the extremely high fat content. Treatment centers on a very strict low-fat diet, typically limiting dietary fat to 10-20 grams per day. There are currently no widely approved drug therapies that specifically correct the underlying protein deficiency, though newer gene therapies and antisense treatments for related conditions are being studied. Managing and preventing pancreatitis episodes is the primary goal of care. With careful dietary management, many patients can reduce the frequency of dangerous complications.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Bring these to your next appointment

• Q1.How low should my daily fat intake be, and can a dietitian help me plan meals?,What are the warning signs of pancreatitis, and when should I go to the emergency room?,Should my family members be tested for this condition or carrier status?,Are there any newer treatments or clinical trials I should know about?,How often should I have my triglyceride levels checked?,Do I need to take vitamin supplements because of my restricted diet?,What should I do if I accidentally eat a high-fat meal — is there an emergency plan?

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