18 year old Abodh is on treatment for his abnormal lipid profile blood tests. All of the following statements are true about familial hypercholesterolemia, except
First, the core concept here is FH. I know that FH is an autosomal dominant disorder caused by mutations in the LDL receptor gene. This leads to high LDL cholesterol levels, increasing the risk of early coronary artery disease. The question is asking which statement is NOT true about FH.
Now, thinking about common misconceptions or incorrect statements about FH. Let's consider typical options. One might be about treatment options. For example, statins are first-line, but in FH, sometimes higher doses or additional therapies like ezetimibe or PCSK9 inhibitors are needed. Another incorrect option might be about the inheritance pattern—since it's autosomal dominant, saying it's recessive would be wrong. Also, some people might confuse FH with other lipid disorders like LPL deficiency. Also, FH presents with xanthomas and corneal arcus at a young age.
So possible options could be:
A. Caused by mutations in the LDL receptor gene.
B. Autosomal recessive inheritance.
C. Presents with tendon xanthomas.
D. Treated with statins as first-line.
If B is the incorrect statement because FH is autosomal dominant, then B would be the correct answer here. Let me check: yes, FH is indeed autosomal dominant. So if an option says it's recessive, that's the exception. Other options like A, C, D are correct. So the correct answer is B.
Now, structuring the explanation. The core concept is FH's genetic basis and clinical features. The correct answer is B because it's autosomal dominant, not recessive. The other options (A, C, D) are accurate. Clinical pearl: remember the inheritance pattern and key clinical features like xanthomas and early CAD. Make sure to explain each option's validity.
**Core Concept**
Familial hypercholesterolemia (FH) is an autosomal **dominant** disorder caused by mutations in the **LDL receptor gene**, leading to elevated low-density lipoprotein (LDL) cholesterol, premature atherosclerosis, and clinical features like tendon xanthomas. It is **not** a recessive condition.
**Why the Correct Answer is Right**
Option B ("Autosomal recessive inheritance") is incorrect because FH is inherited in an **autosomal dominant** pattern. Mutations in the LDL receptor gene reduce cellular uptake of LDL, causing hypercholesterolemia. Homozygous FH (rare) results from inheriting defective genes from **both** parents, but the mode of inheritance remains dominant, not recessive.
**Why Each Wrong Option is Incorrect**
**Option A:** "Caused by mutations in the LDL receptor gene" is **correct**—this is the primary genetic defect in FH.
**Option C:** "Presents with tendon xanthomas" is **correct**—these are hallmark signs due to lipid deposition in tissues.
**Option D:** "Treated with statins as first-line therapy" is **correct**—statins are first-line, though higher-dose or combination therapy may be needed.
**Clinical Pearl /