Familial hypercholesterolemia
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Flashcards
Familial hypercholesterolemia
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Questions
USMLE® Step 1 style questions USMLE
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Reproduced from: Wikimedia Commons
Which of the following conditions has the same inheritance pattern as this patient’s condition?
External References
First Aid
2024
2023
2022
2021
Corneal arcus
familial hypercholesterolemia p. 92
Familial hypercholesterolemia p. 58, 92
presentation p. 720
Tendinous xanthomas p. 307
familial hypercholesterolemia p. 92
Transcript
Content Reviewers
With familial hypercholesterolemia, familial means the disease runs in families, so it has a genetic predisposition, hyper means excess and lastly cholesterolemia refers to the level of cholesterol in the blood.
So, familial hypercholesterolemia is a genetic disorder associated with high levels of cholesterol in the blood.
Now, cholesterol is a lipid molecule, so a type of fat, that normally helps maintain the structure of cell membranes, and is a precursor to steroid hormones, bile acids, and vitamin D.
There are two main types of cholesterol: LDL or Low Density Lipoprotein which is sometimes called “bad cholesterol,” nad HDL or High Density Lipoprotein which is sometimes called “good cholesterol.”
But good and bad is overly simplistic, and like all things - the subtleties matter.
LDL is produced by the liver and it carries cholesterol out to the rest of the body.
If all of the cholesterol from LDL is not completely distributed to the peripheral cells, then HDL brings some of that cholesterol back from the peripheral tissues and sends it to the liver.
Now, what makes LDL bad and HDL good is that, whenever there’s a high blood concentration of LDL, the LDL can be ingested by macrophages that sit along vessel walls, forming atherosclerotic plaques.
Over decades, large atherosclerotic plaques can lead to myocardial infarctions, strokes, and peripheral vascular disease.
That’s why we want to keep LDL blood levels under control.
On the other hand, HDL can remove cholesterol from cells and that can help reverse the process of atherosclerosis.
Now, our body usually keeps LDL cholesterol levels in check by clearing our excess LDL from the plasma.
This is mainly done by the LDL receptors present on the surface of the liver cells.
First, the LDL molecules bind to the LDL receptors, which are clustered in specialized regions of the cell membrane called coated pits.
Summary
Familial hypercholesterolemia (FH) is an autosomal dominant condition in which there are abnormally high levels of LDL cholesterol in the blood. The condition increases a person's risk for heart disease and other serious health problems. FH is caused by defects in one of several genes that control the amount of cholesterol in the blood. People with FH can present with xanthomas (fats build up under the skin), xanthelasma (fats build up in the eyelids), fatty liver, and pancreatitis.