Question

Which of the following conditions is most likely to follow this pattern of inheritance?

• A. Prader-Willi syndrome
• B. Marfan syndrome
• C. Kearns-Sayre syndrome
• D. Duchenne muscular dystrophy

Hint:

Autosomal dominant pedigree usually shows vertical transmission in successive generations.

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
Although the pedigree image is not explicitly provided in the OCR text snippet, the answer key "B" indicates the question refers to an Autosomal Dominant (AD) inheritance pattern.
Step 2: Detailed Explanation:

Marfan Syndrome: This is a classic example of an Autosomal Dominant condition. It involves a mutation in the FBN1 gene on chromosome 15. In an AD pedigree, you see vertical transmission (present in every generation) and a 50% chance of inheritance for each child.

Differential - Prader Willi: This is a complex disorder involving genomic imprinting and deletion on chromosome 15 (paternal origin). It does not follow simple Mendelian AD inheritance.

Differential - Kearns-Sayre: This is a mitochondrial disorder. Inheritance is exclusively maternal (all children of an affected mother are at risk, none of an affected father).

Differential - Duchenne Muscular Dystrophy (DMD): This is an X-linked recessive disorder. It typically affects males, and transmission is through carrier females.

Marfan Characteristics: Tall stature, arachnodactyly, ectopia lentis (upward displacement), and risk of aortic dissection/aneurysm.

Step 3: Final Answer:
Among the options, Marfan syndrome is the one that characteristically follows an Autosomal Dominant pattern of inheritance.