Types of Hyperlipidemia (Based on Cause): Primary Hyperlipidemia

Primary Dyslipidemia

Definition

• Primary Dyslipidemia is a condition resulting from genetic factors (single or multiple gene mutations) that lead to disturbances in the production or clearance of lipoproteins such as LDL, HDL, and triglycerides.

Risk Factors

• Presence of risk factors should raise suspicion in patients with:

  • Premature heart disease

  • Family history of atherosclerotic diseases

  • Serum cholesterol levels greater than 240 mg/dl

  • Physical signs of hyperlipidemia (most common example: being overweight or obesity)

Types of Primary Dyslipidemia

1. Familial Combined Hyperlipidemia

• Onset: Develops in teenagers and young adults

• Pathophysiology:

  • This type is characterized by abnormalities in cholesterol synthesis, resulting in elevated cholesterol levels in the blood.

  • The condition is often inherited and can lead to significant cardiovascular risks if not managed properly.

  • Patients may experience high levels of LDL, low HDL, and elevated triglycerides, necessitating early screening among family members.

2. Familial Hyper-Apo Beta Lipoproteinemia

• Genetic Mutation: Involves a mutation in a specific group of LDL lipoproteins called apolipoproteins.

• Mechanism: Apolipoproteins, including LDL, are primarily produced in the liver and intestine; some can be produced in heart tissues as well.

• Degradation: While most apolipoproteins are degraded in the liver, mutations can prevent adequate degradation, leading to dyslipidemia.

  • The clinical manifestation can include premature atherosclerosis and related cardiovascular diseases.

3. Familial Hypertriglyceridemia

• Characteristics: This type is primarily characterized by high triglyceride levels.

• Underlying Issue: Genetic mutations affect triglyceride metabolism, resulting in significantly elevated triglyceride levels in the blood, which can contribute to pancreatitis and cardiovascular issues if left untreated.

4. Homozygous Familial Hypercholesterolemia

• Genetic Basis: Also known as polygenic hypercholesterolemia, it involves mutations affecting LDL receptors.

• Differentiation: Important to note that familial hyper-apo beta lipoproteinemia and homozygous familial conditions are different; in the former, the LDL itself is mutated, whereas in homozygous familial, it is the receptor that is dysfunctional.

• Clinical Impact: This condition results in extremely high levels of cholesterol from an early age and requires aggressive management to prevent cardiovascular diseases.