Abstract
Purpose :
Myocilin (MYOC) is a gene known to be associated with the development of primary open-angle glaucoma (POAG). In this study, we report two cases of POAG with rare MYOC variants and their clinical phenotypes.
Methods :
Whole-genome sequencing was performed on 510 cases of POAG recruited at Tohoku University Hospital. Cases with MYOC variants with minor allele frequencies less than 0.0001 in 14KJPN, a reference panel based on whole-genome sequencing of 14,000 individuals, were selected.
Results :
One case with the MYOC p.(Ile477Asn) variant and one case with the MYOC p.(Ala488fs) variant were identified.
Case 1: MYOC p.(Ile477Asn) variant
The patient was diagnosed with POAG at age 32. A sibling of the patient had also been diagnosed with glaucoma. The phenotype was hypertensive glaucoma in both eyes. Mean deviation as measured by Humphrey Field Analyzer was -6.09 dB in the right eye and -24.10 dB in the left eye. Selective laser trabeculoplasty and microhook trabeculotomy were performed in both eyes.
Case 2: MYOC p.(Ala488fs) variant
The patient was diagnosed with POAG at age 61. No obvious family history was found in an interview. Untreated intraocular pressure was 22 mmHg in the right eye and 20 mmHg in the left eye. At the time of diagnosis, the patient already had end-stage visual field defects. Trabeculectomy was performed in the right eye twice.
Conclusions :
Both cases had severe visual field defects and required surgical treatment. MYOC p.(Ile477Asn) has been found to be a likely pathogenic variant in studies of people with European ancestry, and this report is the first to identify it in a Japanese population. There have been no reports suggesting pathogenicity of the MYOC p.(Ala488fs) variant, and further research is required in the future.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.