A case of paternity-confirmed de novo R124H mutation resulting in granular corneal dystrophy type 2

Abstract

Purpose: To report the first case of granular corneal dystrophy type 2 (GCD2) caused by a de novo p.(Arg124His) mutation that was confirmed by paternity testing in a 13-year-old male patient referred for the evaluation of corneal opacities in the left eye.Study design: Clinical case report.

Methods: The p.(Arg124His) mutation was identified using direct Sanger sequencing of the entire TGFBI gene. The patient's parents and sister also underwent ophthalmological examination and direct Sanger sequencing of the entire TGFBI gene.

Results: No abnormal findings on ophthalmic examination or genetic mutations were found in the parents. In addition, the patient's biological parents were confirmed using DNA paternity testing.

Conclusion: A negative family history of GCD2 and the absence of GCD2 in the parents of patients seeking refractive surgery are not sufficient to exclude a diagnosis of GCD2 because some cases of GCD2 arise from de novo mutations. Exclusion of GCD2 before refractive surgery requires genetic analysis for the p.(Arg124His) mutation.

Keywords: Avellino corneal dystrophy; Granular corneal dystrophy type 2; de novo R124H mutation; de novo p.(Arg124His) mutation; mutation in germ line.