**Question:** Which of the following corneal dystrophies is an autosomal recessive condition

A. Fuchs' dystrophy
B. Marfan syndrome
C. Stickler syndrome
D. Keratoconus

**Core Concept:** Corneal dystrophies are a group of inherited disorders characterized by the accumulation of abnormal substances in the cornea, leading to its cloudiness and visual impairment. Autosomal recessive conditions are inherited when an individual inherits two copies of the mutated gene: one from each parent.

**Why the Correct Answer is Right:**
Corneal dystrophy type D (Keratoconus) is not autosomal recessive. It is a non-inherited condition, primarily affecting the cornea's collagen structure leading to its conical shape.

**Why Each Wrong Option is Incorrect:**
Option A (Fuchs' dystrophy) is an autosomal dominant disorder, inherited when an individual receives one mutated gene from one parent.

Option B (Marfan syndrome) is a connective tissue disorder affecting multiple systems. It is an autosomal dominant condition, inherited when an individual receives the mutated gene from one parent.

Option C (Stickler syndrome) is also an autosomal dominant condition, inherited through the receipt of one mutated gene from a parent.

**Why Clinical Pearls:**

1. Understanding the inheritance patterns (autosomal dominant, autosomal recessive, X-linked, etc.) is crucial for diagnosing genetic disorders like corneal dystrophies.
2. Corneal dystrophies can be classified into different types (dominant, recessive, X-linked, etc.) based on the mode of inheritance, helping in genetic counseling and predicting risk of transmission to offspring.

**Correct Answer:** D (Keratoconus) is NOT an autosomal recessive condition.