Atypical presentation of macular corneal dystrophy managed by Descemet stripping endothelial keratoplasty

Detailed corneal and genetic characteristics of a pediatric patient with macular corneal dystrophy - case report

BACKGROUND

Corneal dystrophies are a group of rare, inherited disorders that are usually bilateral, symmetric, slowly progressive, and not related to environmental or systemic factors. The majority of publications present the advanced form of the disease with a typical clinical demonstration. The initial signs and symptoms of different epithelial and stromal corneal dystrophies are not specific; therefore, it is very important to establish the early characteristic corneal features of these disorders that could guide the diagnostic process.

CASE PRESENTATION

The main purpose of this study was to report the differential diagnosis of a pediatric patient with bilateral anterior corneal involvement suspected of corneal dystrophy. An 8-year-old male patient presented with asymptomatic, persistent, superficial, bilateral, diffuse, anterior corneal opacities. Slit lamp examination results were not specific. Despite the lack of visible stromal involvement on the slit lamp examination, corneal analysis based on confocal microscopy and optical coherence tomography revealed characteristic features of macular corneal dystrophy (MCD). The diagnosis of MCD was confirmed by CHST6 gene sequencing. The early corneal characteristic features of MCD, established based on the findings of this case report, include corneal astigmatism (not specific), diffuse corneal thinning without a pattern of corneal ectasia (specific), and characteristic features on confocal microscopy (specific), including multiple, dark, oriented striae at different corneal depths.

CONCLUSIONS

The clinical examination should be complemented with corneal imaging techniques, such as confocal microscopy and optical coherence tomography. In patients suspected of corneal dystrophy, genetic testing plays an important role in establishing the final diagnosis.

Macular Corneal Dystrophy: An Updated Review

Macular Corneal Dystrophy is an autosomal recessive form of corneal dystrophy due to a mutation in CHST6 gene, which results in abnormal proteoglycan synthesis. There is accumulation of abnormal glycosaminoglycans in the corneal stroma and endothelium. The deposition results in progressive loss of corneal transparency and visual acuity. The histopathology shows characteristic alcian blue positive deposits. Management in the cases with visual loss requires keratoplasty either full thickness or lamellar. The decision about the ideal type of keratoplasty depends on age and pre-operative clinical features. Although prognosis after keratoplasty is good, recurrences can occur. Future research should be targeted towards gene therapy in this condition.

Clinical diversity in macular corneal dystrophy: an optical coherence tomography study

PURPOSE

To characterise the corneal deposits of macular corneal dystrophy and correlate with high-resolution optical coherence tomography (OCT).

METHODS

A total of 23 eyes of 15 patients were evaluated for clinical features on slit lamp biomicroscopy, and high-resolution OCT was performed to correlate the clinical findings. The deposits were characterised based upon their location and level in the corneal layers.

RESULTS

Mean age was 31.5 (Range 20-67) years. The stromal deposits were restricted to central 8 mm in 9 eyes; in the rest of the 14 eyes, the deposits were seen in both central and peripheral cornea. In one patient, no such distinction could be made due to diffuse nature of the deposits throughout the cornea with sparing of 1-2 mm of the cornea internal to the limbus. The central deposits were in the anterior stromal layers, while the peripheral deposits were in the deep stromal corneal layers and non-contiguous with the anterior stromal deposits. In one patient aged 67 years, the peripheral deposits in deep corneal layers were more prominent than the central anterior stromal deposits and were associated with a significant thickening of Descemet membrane.

CONCLUSIONS

MCD exhibits a clinically diverse presentation as revealed on the clinical and optical coherence tomography study. Immunophenotype and genotype-phenotype correlation may further help in understanding various clinical presentations of MCD.