**Core Concept**
Corneal dystrophies are a group of rare, genetic disorders that affect the cornea, leading to progressive vision loss. These disorders are characterized by the accumulation of abnormal deposits in the corneal stroma, epithelium, or endothelium.

**Why the Correct Answer is Right**
The correct answer is that corneal dystrophies are usually inherited in an autosomal dominant or autosomal recessive pattern. This means that a mutation in one of the two copies of the gene is sufficient to cause the disorder, or a mutation in both copies of the gene is required to cause the disorder, respectively. The genetic mutations that cause corneal dystrophies affect various proteins and pathways involved in corneal structure and function, such as collagen, keratan sulfate, and the crystallins.

**Why Each Wrong Option is Incorrect**
**Option A:** While some corneal dystrophies may be associated with systemic diseases, such as Fabry disease, this is not a defining characteristic of corneal dystrophies in general.
**Option B:** Corneal dystrophies are not typically associated with infections, such as bacterial or viral keratitis.
**Option C:** Corneal dystrophies are not usually caused by environmental factors, such as UV radiation or chemical exposure.

**Clinical Pearl / High-Yield Fact**
A key feature of corneal dystrophies is that they often have a characteristic pattern of inheritance, which can be helpful in diagnosis and genetic counseling. For example, Fuchs endothelial corneal dystrophy is typically inherited in an autosomal dominant pattern, while lattice corneal dystrophy is typically inherited in an autosomal recessive pattern.

**Correct Answer:** D.