Korean J Ophthalmol.  2013 Dec;27(6):454-458. 10.3341/kjo.2013.27.6.454.

A Case of Korean Patient with Macular Corneal Dystrophy Associated with Novel Mutation in the CHST6 Gene

Affiliations
  • 1Department of Ophthalmology, The Catholic University of Korea College of Medicine, Seoul, Korea. eyedoc@catholic.ac.kr
  • 2Medical and Scientific Affairs, Allergan Korea Ltd., Seoul, Korea.

Abstract

To report a novel mutation within the CHST6 gene, as well as describe light and electron microscopic features of a case of macular corneal dystrophy. A 59-year old woman with macular corneal dystrophy in both eyes who had decreased visual acuity underwent penetrating keratoplasty. Further studies including light and electron microscopy, as well as DNA analysis were performed. Light microscopy of the cornea revealed glycosaminoglycan deposits in the keratocytes and endothelial cells, as well as extracellularly within the stroma. All samples stained positively with alcian blue, colloidal iron, and periodic acid-Schiff. Electron microscopy showed keratocytes distended by membrane-bound intracytoplasmic vacuoles containing electron-dense fibrillogranular material. These vacuoles were present in the endothelial cells and between stromal lamellae. Some of the vacuoles contained dense osmophilic whorls. A novel homozygous mutation (c.613 C>T [p.Arg205Trp]) was identified within the whole coding region of CHST6. A novel CHST6 mutation was detected in a Korean macular corneal dystrophy patient.

Keyword

Carbohydrate sulfotransferase; Corneal dystrophies, hereditary; Microscopy, electron; Microscopy, polarized; Mutation, missense

MeSH Terms

Corneal Dystrophies, Hereditary/diagnosis/*genetics/metabolism
Corneal Keratocytes/ultrastructure
DNA/*genetics
DNA Mutational Analysis
Female
Humans
Microscopy, Electron
Middle Aged
*Mutation, Missense
Pedigree
Polymerase Chain Reaction
Republic of Korea
Sulfotransferases/*genetics/metabolism
DNA
Sulfotransferases

Figure

  • Fig. 1 Slit lamp photography of the patient (A,B). (A) Right eye and (B) left eye. Diffusely hazy corneas with bilateral opacities were observed. There were multiple irregular, grayish-white, dense, poorly delineated spots in the stroma. Slit lamp photography of the patient's son (C,D). (C) Right eye and (D) left eye. Haziness of the stroma with diffuse opacities was observed in both eyes. These findings were similar, but less severe in appearance compared to his mother's examination.

  • Fig. 2 Comparison between light microscopic appearances (×100). The arrows indicate positive findings for glycosaminoglycan. (A) Hematoxylin and eosin stain, (B) alcian blue stain, (C) colloidal iron stain, (D) periodic acid-Schiff stain, and (E) Masson's trichrome stain.

  • Fig. 3 Transmission electron microscopic findings. (A) Keratocyte distended by membrane-bound intracytoplasmic vacuoles containing electron dense fibrillogranular material (black arrow). Vacuole containing dense fibrillogranular material in the interstromal lamellae (white arrow). Asterisk indicates relatively normal keratocyte (scale bar, 2 µm). (B) Keratocyte with vacuoles containing dense osmophilic whorls (scale bar, 0.5 µm).

  • Fig. 4 Direct sequencing analysis of the coding region of CHST6. (A) DNA sequence of the patient. (B) DNA sequence of the patient's son. Sequence of the entire coding region of CHST6 revealed a change in the nucleotide at codon 205 (CGG→TGG). The same mutation was identified in the patient's son (p.Arg205Trp [c.613C>T]).


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