Final answer:
The patient with normal serum biomarkers but hypercholesterolemia likely has Type IIa Familial hypercholesterolemia, a condition characterized by elevated LDL cholesterol.
Step-by-step explanation:
If serum biomarkers are normal but hypercholesterolemia is present, it suggests that the patient may have a form of hyperlipidemia that specifically affects cholesterol levels rather than triglycerides. Given the presence of hypercholesterolemia, the disease in question could be Type IIa Familial hypercholesterolemia. This condition is characterized by elevated levels of low-density lipoprotein (LDL) cholesterol due to mutations affecting the LDL receptor, leading to an increased plasma total cholesterol level. Unlike hyperlipoproteinemia type I, IIb, III, IV, and V, where other lipoproteins or triglyceride levels are also affected, Type IIa solely involves LDL cholesterol levels.