AB090. MOG1, the genetic modifier at 20q13, delays the age-at-onset of glaucoma by 8 to 10 years

Background: Primary open-angle glaucoma (POAG) is a genetically complex disorder caused primarily by gene-gene interactions. To identify these interactions, we studied the CA family, a large French-Canadian pedigree in which the myocilin K423E mutation (MYOCK423E) causes autosomal dominant glaucoma with diagnoses ranging from juvenile-onset OAG (JOAG) to late adult-onset POAG in the heterozygotes (HTZ). To explain this extreme variability, we hypothesized that a second gene, called a modifier, was interacting with MYOC, the primary disease gene. Our goals were (I) to map the modifier on the human genome and; (II) to characterize the symptoms affected genetically by the modifier. These symptoms are called endophenotypes.