A rare optineurin mutation in an Indian family with coexistence of JOAG and PCG

Abstract

Purpose: This study focused on the genetic screening of Myocilin (MYOC), Cytochrome P450 family 1 subfamily B member 1 (CYP1B1), Optineurin (OPTN), and SIX homeobox 6 (SIX6) genes in a family with coexistence of primary congenital glaucoma (PCG) and juvenile open-angle glaucoma (JOAG). Methods: Sanger sequencing was used to examine the coding region of all four genes. Six different online available algorithms were used for the pathogenicity prediction of missense variant. Structural analysis was done using Garnier–Osguthorpe–Robson (GOR), PyMol, ChimeraX, and Molecular Dynamic (MD) Simulations (using Graphics Processing Unit (GPU)-enabled Desmond module of Schrödinger). Results: There were a total of three sequence variants within the family. All seven algorithms determined that a single mutation, G538E, in the OPTN gene is pathogenic. The loops connecting the strands became more flexible, as predicted structurally and functionally by pathogenic mutations. Mutations create perturbations and conformational rearrangements in proteins, hence impairing their functioning. Conclusion: In this study, we describe a North Indian family in which members were having JOAG and PCG due to a rare homozygous/heterozygous mutation in OPTN. The coexistence of two types of glaucoma within a single pedigree suggests that certain OPTN mutations may be responsible for the onset of different glaucoma phenotypes.