Myocilin Genetic Testing for POAG Allows Early Identification in At-Risk Patients
Ophthalmology, March 2017
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.