Question

A family pedigree reveals multiple individuals with progressive eye movement limitation, retinal pigment changes, and disturbances in cardiac conduction. Based on these findings and the inheritance pattern, which of the following is the most probable diagnosis?

• A. Duchenne muscular dystrophy
• B. Kearns--Sayre syndrome
• C. Friedreich ataxia
• D. Myotonic dystrophy

Hint:

Progressive external ophthalmoplegia + pigmentary retinopathy + heart block = Kearns--Sayre syndrome.

Answer 1

The Correct Option is B

Concept: Kearns--Sayre syndrome is a mitochondrial disorder. It is characterized by progressive external ophthalmoplegia, pigmentary retinopathy, and cardiac conduction defects.

Step 1: Identify the classic triad.
The given features are: \[ \text{Eye movement limitation + retinal pigment changes + cardiac conduction defect} \]

Step 2: Match with syndrome.
This triad is typical of: \[ \text{Kearns--Sayre syndrome} \]

Step 3: Understand inheritance.
Kearns--Sayre syndrome is related to mitochondrial DNA abnormalities, so inheritance may show maternal or mitochondrial pattern. Therefore, the correct answer is Kearns--Sayre syndrome.