HLA-B* 1502 is a genetic marker for
**Core Concept**
The HLA-B*1502 allele is a specific genetic marker associated with an increased risk of severe cutaneous adverse reactions (SCARs), including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), particularly in certain ethnic populations.
**Why the Correct Answer is Right**
HLA-B*1502 is a human leukocyte antigen (HLA) allele that plays a crucial role in the presentation of drugs to the immune system. Individuals carrying this allele are at a higher risk of developing SCARs, such as SJS and TEN, in response to certain medications, including carbamazepine, phenytoin, and lamotrigine. This is because the HLA-B*1502 allele can lead to the formation of drug-reactive T-cells, which can cause a severe immune-mediated reaction.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because HLA-B*1502 is not associated with an increased risk of liver toxicity, which is a potential side effect of certain medications, including acetaminophen and statins.
**Option B:** This option is incorrect because HLA-B*1502 is not a genetic marker for an increased risk of cardiovascular disease, which is a major risk factor for conditions such as atherosclerosis and myocardial infarction.
**Option C:** This option is incorrect because HLA-B*1502 is not associated with an increased risk of infections, which can be caused by a variety of factors, including immunosuppression and genetic predisposition.
**Clinical Pearl / High-Yield Fact**
When prescribing medications known to be associated with SCARs, such as carbamazepine and phenytoin, it is essential to screen patients for the presence of the HLA-B*1502 allele, particularly in high-risk ethnic populations, to minimize the risk of severe adverse reactions.
**Correct Answer:** D.