Question

The pedigree given below shows individuals affected (shaded circles/rectangles) by chronic hypertension. Assuming 100% penetrance, the inheritance of this trait is

• A. autosomal dominant
• B. autosomal recessive
• C. sex-linked dominant
• D. sex-linked recessive

Answer 1

The Correct Option is A

The given pedigree chart shows individuals affected by chronic hypertension, indicated by shaded circles and rectangles. Our task is to determine the mode of inheritance, assuming 100% penetrance.

Let's analyze the information:

1. Affected Individuals: In this chart, affected individuals are present in every generation, indicating a continuous pattern of inheritance.
2. Gender Distribution: Both males and females are equally affected, which suggests that the trait is not sex-linked.
3. Pattern of Inheritance:
   • If the trait were autosomal recessive, we would expect to see skipped generations where carriers do not show the trait. However, there are no skipped generations shown in the pedigree.
   • If the trait were sex-linked (either dominant or recessive), we would expect a specific pattern of inheritance based on the sex chromosomes, such as more males being affected for recessive traits or affected fathers passing the trait to all daughters for dominant traits. These patterns are not observed in the given chart.
   • The continuous presence of the trait in every generation without gender bias supports an autosomal dominant mode of inheritance.

Conclusion: The pattern observed in the pedigree chart corresponds to an autosomal dominant trait. Thus, the correct answer is autosomal dominant.