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primary hypoalphalipoproteinemia 2

Description

Primary hypoalphalipoproteinemia-2, also known as familial HDL deficiency, is an autosomal recessive disorder characterized by dysfunctional apoA-I production.

  • This condition results in undetectable levels of apoA-I, a crucial protein involved in the formation and metabolism of high-density lipoproteins (HDL) in the blood [1].
  • Primary hypoalphalipoproteinemia-2 is caused by mutations in the ABCA1 gene, which plays a key role in cholesterol efflux from cells to HDL particles [8].
  • As a result, individuals with this condition have low levels of HDL cholesterol, often below 10 mg/dl [9].

This disorder can lead to an increased risk of early familial coronary heart disease (CHD), as approximately 20-30% of cases are attributed to hypoalphalipoproteinemia or high-density lipoprotein deficiency [3].

Additional Characteristics

  • undetectable levels of apoA-I
  • dl
  • increased risk of early familial coronary heart disease (CHD)
  • high-density lipoprotein deficiency

Signs and Symptoms

Signs and Symptoms of Primary Hypoalphalipoproteinemia 2

Primary hypoalphalipoproteinemia-2, also known as Tangier disease, is a rare genetic disorder characterized by the complete absence or extremely low levels of apolipoprotein AI (apoAI) and high-density lipoprotein (HDL) in the blood. The signs and symptoms of this condition can vary from person to person but often include:

  • Disturbances in nerve function: People with Tangier disease may experience numbness, tingling, or weakness in their hands and feet [1].
  • Enlarged, orange-colored tonsils: This is a distinctive feature of the disease, where the tonsils become enlarged and take on an orange color due to the accumulation of lipids [4].
  • Blurred vision: Some individuals may experience blurred vision or other eye problems due to corneal clouding [6].
  • Raised fatty bumps on the skin: These are typically yellow in color but can also appear orange, red, or brown and are a result of planar xanthomas [6].

It's essential to note that these symptoms can be similar to those experienced by people with other conditions, so an accurate diagnosis requires medical evaluation.

References: [1] - People with Tangier disease have additional signs and symptoms, such as disturbances in nerve function; enlarged, orange-colored tonsils; and ... [4] - Nov 1, 2012 — People with Tangier disease have additional signs and symptoms, such as disturbances in nerve function; enlarged, orange-colored tonsils; and ... [6] - What are the signs and symptoms? · Blurred vision · Raised fatty bumps on the skin that are typically yellow, but can also appear orange, red, or brown in colour ...

Additional Symptoms

  • Disturbances in nerve function
  • Enlarged, orange-colored tonsils
  • Raised fatty bumps on the skin
  • blurred vision

Diagnostic Tests

Diagnostic Tests for Primary Hypoalphalipoproteinemia 2

Primary hypoalphalipoproteinemia 2 (PH2) is a rare genetic disorder characterized by low levels of high-density lipoprotein (HDL) in the blood. Accurate diagnosis is crucial to confirm the presence of PH2 and rule out other conditions that may cause similar symptoms.

Diagnostic Tests:

  • Electrocardiogram (ECG): An ECG can help identify any cardiac abnormalities associated with PH2 [5].
  • Exercise (treadmill) stress test: This test can assess cardiovascular function and detect any potential issues related to low HDL levels [5].
  • Evaluation of HDL subfractions: Measuring the different components of HDL can provide valuable information about the severity of PH2 [3].
  • Measurement of the LCAT enzymatic activity: Low-density lipoprotein cholesterol acyltransferase (LCAT) enzyme activity is often impaired in individuals with PH2, and measuring its activity can help confirm the diagnosis [5].

Genetic Testing:

  • Accurate diagnosis: Genetic testing can confirm the presence of gene mutations associated with primary hypoalphalipoproteinemia 2, providing a definitive diagnosis [6].

Additional Diagnostic Tests

  • Electrocardiogram (ECG)
  • Exercise (treadmill) stress test
  • Evaluation of HDL subfractions
  • Measurement of the LCAT enzymatic activity

Treatment

Treatment Options for Primary Hypoalphalipoproteinemia

Primary hypoalphalipoproteinemia, also known as low HDL cholesterol, can be treated with various medications and lifestyle changes.

  • Statin Therapy: Statins, such as HMG-CoA reductase inhibitors, are often prescribed to reduce LDL (bad) cholesterol levels. In clinical trials, a 2 mg/d dose of statin therapy has been shown to reduce total cholesterol and LDL-C levels [2].
  • Ezetimibe: This medication inhibits cholesterol absorption in the small intestine, reducing plasma concentrations of plant sterols in patients. The combination of ezetimibe with other lipid-lowering therapies may be effective in managing hypoalphalipoproteinemia [4].

Other Treatment Options

In addition to medications, a low-fat diet and regular exercise can help manage primary hypoalphalipoproteinemia. However, these lifestyle changes alone may not be sufficient to raise HDL cholesterol levels.

  • Gemfibrozil: This medication has been shown to increase HDL-C levels in patients with isolated hypoalphalipoproteinemia [9].
  • Nicotinic Acid: Nicotinic acid therapy can also help raise HDL-C levels, although it may have side effects such as flushing and itching [9].

Important Considerations

It's essential to note that the management of primary hypoalphalipoproteinemia requires care coordination and management from an interprofessional team consisting of a primary care clinician, lipid specialist, and other healthcare professionals [3]. Treatment should be individualized based on the patient's specific needs and medical history.

References: [2] - Statin therapy has proven risk reduction in both primary and secondary prevention of cardiovascular disease. Statins modestly increase HDL-C by 1-5% [5]. [3] - The management of hypoalphalipoproteinemia requires care coordination and management from the interprofessional team consisting of a primary care clinician, lipid specialist, and other healthcare professionals. [4] - Treatment with ezetimibe, which inhibits cholesterol absorption, reduces the plasma concentrations of plant sterols in patients. [9] - Gemfibrozil, nicotinic acid and combination therapy in patients with isolated hypoalphalipoproteinemia: a randomized, open-label, crossover study

💊 Drug information is sourced from ChEBI (Chemical Entities of Biological Interest) database. Always consult with a healthcare professional before starting any medication. Click on any medication name for detailed information.

Differential Diagnosis

Differential Diagnosis of Primary Hypoalphalipoproteinemia 2

Primary hypoalphalipoproteinemia-2 is a rare genetic disorder characterized by dysfunctional apoA-I production, resulting in undetectable levels of high-density lipoprotein (HDL) cholesterol in the blood. When diagnosing this condition, it's essential to rule out other possible causes of low HDL-C values.

Causes of Low HDL-C Values

According to a study [6], the differential diagnosis for primary hypoalphalipoproteinemia-2 includes:

  • Tangier disease: A rare genetic disorder that affects the production of apolipoproteins, leading to extremely low levels of HDL cholesterol.
  • LCAT deficiency: A condition characterized by a deficiency in the enzyme lecithin-cholesterol acyltransferase (LCAT), which is essential for the formation of HDL cholesterol.
  • Secondary causes: Extremely low HDL cholesterol levels can also be caused by secondary factors, such as:
    • Obesity: Being significantly overweight or obese can lead to low HDL cholesterol levels.
    • Smoking: Smoking cigarettes can lower HDL cholesterol levels and increase the risk of heart disease.
    • Diabetes: Having diabetes can also contribute to low HDL cholesterol levels.

Other Considerations

When diagnosing primary hypoalphalipoproteinemia-2, it's crucial to consider other rare genetic disorders that may present with similar symptoms. These include:

  • Familial primary hypoalphalipoproteinemia: A condition characterized by low levels of HDL cholesterol due to a genetic mutation.
  • Hypoalphalipoproteinemia (HA): A broader term that encompasses various conditions associated with low HDL cholesterol levels.

References

[5] Primary hypoalphalipoproteinemia-2 is an autosomal recessive disorder characterized by dysfunctional apoA-I production, resulting in undetectable levels of high-density lipoprotei% (HDL) in the blood. [6] Download Table | Differential diagnosis: Causes of low HDL-C values [adapted from 4-7] [7] The differential diagnosis includes Tangier disease, LCAT deficiency (see these terms) and secondary causes of extremely low HDL cholesterol levels that include obesity, smoking, and diabetes.

Additional Differential Diagnoses

Additional Information

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A hypolipoproteinemia that is characterized by dysfunctional apoA-I production, resulting in undetectable levels of apoA-I in serum and in markedly low levels of serum high density lipoprotein cholesterol, is generally an autosomal recessive disorder associated with extensive atherosclerosis, xanthomas, and corneal opacities, and that has_material_basis_in homozygous, compound heterozygous, or heterozygous mutation in the APOA1 gene on chromosome 11q23.
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