Phenotypic non-penetrance in granular corneal dystrophy type II

Abstract

Purpose: To report a possible case of phenotypic non-penetrance in granular corneal dystrophy type II (GCD-II).

Methods: DNA analysis was performed on 11 patients with white granular corneal opacities and 50 normal controls after informed consent was obtained. The TGFBI gene was analyzed by sequencing DNA from epidermal keratinocytes obtained using adhesive tape.

Results: The heterozygous R124H mutation of TGFBI gene was found in all 11 patients. Although 49 normal controls had no mutation in the TGFBI gene, one normal control, a 26-year-old man, had the heterozygous R124H mutation of TGFBI gene. His 55-year-old father had the same mutation, but no corneal opacities.

Conclusion: As not all mutations are expressed in the phenotype, GCD-II gene mutation may have non-penetrance. This report documents a possible case of phenotypic non-penetrance in GCD-II.