Abstract
Purpose::
We aimed to assess potential modifying effects of the WDR36 gene in primary open angle glaucoma (POAG) families with known Myocilin (MYOC) mutations.
Methods::
Our previous screening of MYOC gene in 320 unrelated familial and sporadic POAG revealed 11 different disease-causing mutations in a total of 19 cases, 7 with juvenile (JOAG) and 12 with adult-onset POAG. In this study, genomic DNA from the affected subjects of the same families were directly sequenced for 23 coding exons and their immediate intron-exon boundaries of the WDR36 gene.
Results::
DNA sequencing of WDR36 in 19 JOAG/POAG cases with prior MYOC mutations revealed a total of 15 intronic or coding DNA variations, including 4 new SNPs. Only one well-documented juvenile-onset Edinburgh family with prior MYOC-Q337R mutation also showed a novel change (P31T) in the WDR36 gene. Although the MYOC-Q337R mutation was present in all of the 5 living affected individuals of this family, only 3 of them had the WDR36-P31T mutation (reported ranges at the time of diagnosis: age of onset 11, 16, 21; IOP: 28-55 mmHg; CDR: 0.3-0.7) and the other 2 affected members (onset: 5, 17; IOP: 32-36; CDR: 0.8-0.9) did not show this change. No consistent clinical differences were observed in the affected subjects with only one (MYOC) or two (MYOC & WDR36) gene mutations. Two unaffected individuals aged 12 and 10 also had the WDR36-P31T mutation but only the younger subject had the MYOC-Q337R mutation. Therefore, presence of WDR36-P31T mutation in this normal subject with MYOC-Q337R may play a minor age-delayed protective effect. None of the other 18 families with either juvenile- or adult-onset POAG showed a significant change in WDR36.
Conclusions::
Since only 1 of the 19 unrelated JOAG/POAG individuals had both MYOC and WDR36 mutations and, as there were no co-segregation and/or significant clinical deviations among the affected members with or without 2 gene mutations, it is unlikely that the phenotypic effect of Myocilin mutations are modified by WDR36 gene variations.Supported by EY-009947 and M01RR-06192.
Keywords: gene modifiers • candidate gene analysis • intraocular pressure