Following is a disorder of X-linked inheritance
## **Core Concept**
The question pertains to X-linked inheritance patterns, which involve genes located on the X chromosome. Disorders with X-linked inheritance often exhibit specific patterns of transmission from parents to offspring, notably affecting males (who have one X and one Y chromosome) more frequently than females (who have two X chromosomes). This is because males have no second X chromosome to compensate for the defective gene.
## **Why the Correct Answer is Right**
Without the specific options provided, we can infer that the correct answer, likely a condition known to be inherited in an X-linked pattern, would involve a disorder that predominantly affects males and follows a characteristic inheritance pattern. Common examples of X-linked disorders include **Hemophilia A and B** (deficiencies in clotting factors VIII and IX, respectively), **Duchenne Muscular Dystrophy** (a progressive muscle weakness disorder), and **Fragile X Syndrome** (a cause of intellectual disability). These conditions are notable for their X-linked recessive inheritance pattern, where males are more frequently affected than females.
## **Why Each Wrong Option is Incorrect**
- **Option A:** Without specifics, we can't directly address why this option is incorrect, but if it's not an X-linked disorder, it would not follow the characteristic inheritance patterns associated with X-linked conditions.
- **Option B:** Similarly, if this option does not represent an X-linked disorder, it would be incorrect based on its inheritance pattern not matching X-linked conditions.
- **Option C:** If this option does not fit the known X-linked disorders, it would be incorrect for the same reason.
## **Clinical Pearl / High-Yield Fact**
A key point to remember is that X-linked recessive disorders often seem to "skip" generations and predominantly affect males. Female carriers of X-linked recessive disorders have a 50% chance of passing the mutated gene to each son (who would be affected) and to each daughter (who would typically be a carrier like her mother).
## **Correct Answer: D.**