Tylosis is associated with –
**Core Concept**
Tylosis is a rare genetic disorder characterized by thickening of the skin on the palms and soles, leading to hyperkeratosis. This condition is often associated with an increased risk of esophageal cancer, highlighting the importance of genetic predisposition in cancer development.
**Why the Correct Answer is Right**
Tylosis is strongly associated with mutations in the _RHBDF2_ gene, which encodes a protein involved in the regulation of keratinocyte proliferation and differentiation. Individuals with tylosis are at an increased risk of developing esophageal cancer, particularly squamous cell carcinoma, due to the accumulation of genetic mutations in the esophageal epithelium. The association between tylosis and esophageal cancer underscores the significance of genetic predisposition in cancer development.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because tylosis is not primarily associated with mutations in the _TP53_ gene, which is more commonly linked to Li-Fraumeni syndrome.
**Option B:** This option is incorrect because epidermolysis bullosa is a distinct genetic disorder characterized by skin fragility and blistering, not thickening of the skin on the palms and soles.
**Option C:** This option is incorrect because porphyria cutanea tarda is a disorder of heme synthesis, not a genetic disorder of keratinocyte proliferation and differentiation.
**Clinical Pearl / High-Yield Fact**
Tylosis is a rare genetic disorder that highlights the importance of genetic screening in patients with a family history of esophageal cancer. A high index of suspicion for tylosis is essential in patients presenting with hyperkeratosis of the palms and soles, particularly in those with a family history of esophageal cancer.
**Correct Answer:** C.