Congenital stromal corneal dystrophy

A rare genetic eye disorder affecting the cornea

Congenital stromal corneal dystrophy (CSCD) is a rare genetic disorder that affects the cornea, the transparent front part of the eye. This condition is characterized by the presence of cloudy, opalescent spots in the corneal stroma, which can lead to visual impairment. CSCD is present at birth and is typically inherited in an autosomal dominant pattern.

Pathophysiology

The cornea is composed of several layers, including the epithelium, stroma, and endothelium. In congenital stromal corneal dystrophy, the primary abnormality occurs in the corneal stroma, which is the thick, transparent middle layer of the cornea. The stroma is responsible for maintaining the cornea's shape and clarity. In CSCD, abnormal deposits of collagen and other substances accumulate in the stroma, leading to the characteristic cloudiness and opalescence.

Genetics

CSCD is caused by mutations in the DCN gene, which encodes the protein decorin. Decorin is involved in the regulation of collagen fibril formation and organization in the corneal stroma. Mutations in the DCN gene disrupt normal decorin function, leading to the abnormal deposition of collagen and other matrix components in the cornea.

Clinical Features

Individuals with congenital stromal corneal dystrophy typically present with:

• Bilateral corneal clouding present at birth or in early childhood
• Opalescent spots in the corneal stroma
• Progressive visual impairment
• Photophobia (sensitivity to light)

The severity of visual impairment can vary, with some individuals experiencing significant vision loss, while others may have only mild symptoms.

Diagnosis

The diagnosis of CSCD is based on clinical examination and family history. Key diagnostic features include:

• Slit-lamp examination revealing opalescent spots in the corneal stroma
• Family history consistent with autosomal dominant inheritance
• Genetic testing to identify mutations in the DCN gene

Management

There is currently no cure for congenital stromal corneal dystrophy. Management focuses on alleviating symptoms and improving vision. Treatment options may include:

• Corrective lenses to improve visual acuity
• Phototherapeutic keratectomy (PTK) to remove superficial corneal opacities
• Corneal transplantation in severe cases where vision is significantly impaired

Prognosis

The prognosis for individuals with CSCD varies depending on the severity of the condition. While some individuals may maintain relatively good vision with appropriate management, others may experience progressive vision loss. Regular follow-up with an ophthalmologist is essential to monitor the condition and adjust treatment as needed.

Related pages

• Corneal dystrophy
• Genetic disorders
• Ophthalmology