Familial occurrence of pseudoexfoliation in Canada

Background: Genetic factors may play an important role in pseudoexfoliation syndrome. We describe the familiar occurrence of pseudoexfoliation in Cana dian families. Methods: Probands with pseudoexfoliation were referred to a tertiary care g laucoma service in Ottawa because of a family history of pseudoexfoliation or glaucoma, or both. Probands and family members who agreed to participate underwent a systematic interview and eye examination. The pseudoexfoliatio n status was classified as affected, suspect or unknown based on preestabli shed criteria for the diagnosis of pseudoexfoliation and glaucoma. Results: Thirty-four members of 10 families were assessed (18 affected, 2 s uspect and 14 status unknown). Six families had two or more generations wit h pseudoexfoliation, and four families had one generation affected. There w as a predominance of females among the affected subjects (17:1), and transm ission in all cases appeared to be maternal. Eight of the families were of Irish/Scottish ancestry. Nine (50%) of the affected subjects had cardiovasc ular disease. Affected subjects tended to be older than suspects and those whose status was unknown (mean age 77, 67 and 55 years respectively). Seven subjects were affected unilaterally and II bilaterally. Affected subjects had moderate angle pigmentation in both eyes (mean +2.7, where 0 = no pigme nt and +4 = dense homogeneous pigment). The mean intraocular pressure in bo th eyes was higher for the affected subjects (23. 1 [standard deviation (SD ) 8.6] mm Hg) than for the suspects (16.8 [SD 6.1] mm Hg) and those of unkn own status (16.8 [SD 2.9] mm Hg). An enlarged cup:disc ratio was seen in th e affected subjects (mean 0.62). Eleven (61%) of the affected subjects had open angles on gonioscopy, and five had occludable angles and required peri pheral iridectomy. Ten (56%) of the affected subjects were classified as ha ving glaucoma, and 14 (78%) had evidence of cataract formation in at least one eye.