Question

Type-I hyperlipoproteinemia is characterized by

• A. Elevated LDL
• B. Elevated HDL
• C. Elevated chylomicrons
• D. Elevated lipoprotein lipase

Answer 1

The Correct Option is C

Type-I hyperlipoproteinemia, also known as familial hyperchylomicronemia, is a rare inherited disorder characterized by an elevated level of chylomicrons in the blood. This condition is caused by a deficiency in the enzyme lipoprotein lipase or the presence of a defective apolipoprotein C-II, both of which play critical roles in the breakdown of triglycerides carried by chylomicrons.

Pathophysiology:

1. Under normal conditions, dietary fats are packaged into chylomicrons in the intestines, which then enter the bloodstream.
2. Lipoprotein lipase, activated by apolipoprotein C-II, breaks down the triglycerides in chylomicrons into free fatty acids and glycerol for energy use or storage.
3. In type-I hyperlipoproteinemia, due to the enzyme deficiency or defect in the activating protein, chylomicrons are not broken down effectively and accumulate in the bloodstream.

Clinical Features:

• Marked hypertriglyceridemia due to elevated chylomicrons.
• Presence of eruptive xanthomas, hepatosplenomegaly, and lipemia retinalis.
• Presents often in childhood with abdominal pain due to pancreatitis.

Diagnosis:

• Elevated plasma triglyceride levels.
• Laboratory tests revealing the accumulation of chylomicrons.
• Genetic testing may confirm mutations causing the enzyme deficiency.

Treatment:

• Low-fat diet to minimize chylomicron formation.
• Management of complications such as pancreatitis.

Conclusion:Type-I hyperlipoproteinemia is characterized by elevated chylomicrons. This condition results from impaired clearance of chylomicrons due to enzyme deficiencies or defects.