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  • Myocilin Genetic Testing for POAG Allows Early Identification in At-Risk Patients

    By Marianne Doran and selected by George B. Bartley, MD
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    Journal Highlights

    Ophthalmology, March 2017

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    Souzeau et al. compared disease severity between 2 groups of patients with primary open-angle glaucoma (POAG) who had a Myocilin (MYOC) disease-causing variant: those who were diagnosed through normal clinical pathways (Clinical) versus those who were ex­amined following positive results from genetic testing (Genetic). The research­ers found that POAG was identified at an earlier stage in the Genetic group.

    This study retrospectively examined records from the Australian and New Zealand Registry of Advanced Glauco­ma (ANZRAG); 97 MYOC mutation carriers were identified in the data­base, of whom 73 had clinical details available from their initial presentation. Among these 73 participants, 43 were Clinical cases and 30 were Genetic.

    All cases were classified into 4 groups (unaffected, glaucoma suspect, glau­coma, advanced glaucoma) according to disease severity at the time of their first examination by an ophthalmolo­gist. The main outcome measures were glaucoma clinical parameters and age at presentation.

    At the first examination, 83% of Genetic cases were unaffected, and 17% were glaucoma suspects. In contrast, among Clinical cases, 44% were glau­coma suspects, 28% had glaucoma, and 28% had advanced glaucoma. Genetic cases were significantly younger atpresentation than were Clinical cases (40.6 vs. 47.5 years, respectively; p = .018). Glaucoma parameters forthe Clinical and Genetic groups, respectively, included the following: mean highest intraocular pressure, 32.2 vs. 17.6 mm Hg (p < .001); cup-to-disc ratio, 0.65 vs. 0.48 (p = .006); and mean devi­ation on visual field testing, –10.0 vs. –1.2 (p < .001).

    The researchers con­cluded that their findings demonstrate that MYOC cascade genetic testing for POAG allows identification of at-risk individuals at an early stage, even before signs of glaucoma are apparent. Further, they noted that, to their knowledge, this is the first study to demonstrate the clin­ical utility of predictive genetic testing for MYOC in glaucoma.

    The original article can be found here.