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Myocilin predictive genetic testing for primary open-angle glaucoma leads to early identification of at-risk individuals

Citation

Souzeau, E and Tram, KH and Witney, M and Ruddle, JB and Graham, SL and Healey, PR and Goldberg, I and Mackey, DA and Hewitt, AW and Burdon, KP and Craig, JE, Myocilin predictive genetic testing for primary open-angle glaucoma leads to early identification of at-risk individuals, Ophthalmology, 124, (3) pp. 303-309. ISSN 0161-6420 (2017) [Refereed Article]

Copyright Statement

Copyright 2016 American Academy of Opthalmology

DOI: doi:10.1016/j.ophtha.2016.11.011

Abstract

Purpose: To assess the difference in severity of disease in primary open-angle glaucoma (POAG) patients with a Myocilin (MYOC) disease-causing variant who presented through normal clinical pathways (Clinical cases) versus those who were examined following genetic testing (Genetic cases).

Design: Retrospective clinical and molecular study.

Participants: Seventy-three MYOC mutation carriers identified through the Australian and New Zealand Registry of Advanced Glaucoma.

Methods: Individuals were classified based on how they first presented to an ophthalmologist: Clinical cases were referred by their general practitioner or optometrist, and Genetic cases were referred following positive results from genetic testing for the previously identified familial MYOC variant (cascade genetic testing). All cases were then sub-classified into 4 groups (unaffected, glaucoma suspect, glaucoma, advanced glaucoma) according to the severity of disease at the time of their first examination by an ophthalmologist.

Main Outcome Measures: Glaucoma clinical parameters and age at presentation.

Results: At their first examination, 83% of Genetic cases were unaffected and 17% were glaucoma suspect, whereas among Clinical cases 44% were glaucoma suspect, 28% had glaucoma, and 28% had advanced glaucoma. Genetic cases were significantly younger at presentation than Clinical cases (40.6±12.5 vs. 47.5±16.7 years; P = 0.018). The mean highest intraocular pressure (32.2±9.7 vs. 17.6±3.6 mmHg; P < 0.001), cup-to-disc ratio (0.65±0.27 vs. 0.48±0.13; P = 0.006), and mean deviation on visual field testing (-10.0±10.3 vs. -1.2±1.2; P < 0.001) were all significantly worse in Clinical cases compared with Genetic cases. Individuals with common MYOC p.Gln368Ter variant were further analyzed separately to account for the phenotypic variability of different disease-causing variants. All findings remained significant after adjusting for the common MYOC p.Gln368Ter variant.

Conclusions: Our findings demonstrated that MYOC cascade genetic testing for POAG allows identification of at-risk individuals at an early stage or even before signs of glaucoma are present. To our knowledge, this is the first study to demonstrate the clinical utility of predictive genetic testing for MYOC glaucoma.

Item Details

Item Type:Refereed Article
Keywords:glaucoma, genetic testing
Research Division:Medical and Health Sciences
Research Group:Ophthalmology and Optometry
Research Field:Ophthalmology
Objective Division:Health
Objective Group:Clinical Health (Organs, Diseases and Abnormal Conditions)
Objective Field:Hearing, Vision, Speech and Their Disorders
Author:Mackey, DA (Professor David Mackey)
Author:Hewitt, AW (Dr Alex Hewitt)
Author:Burdon, KP (Associate Professor Kathryn Burdon)
ID Code:121359
Year Published:2017
Web of Science® Times Cited:3
Deposited By:Menzies Institute for Medical Research
Deposited On:2017-09-26
Last Modified:2017-11-23
Downloads:0

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