Familial occurrence of pigment dispersion syndrome

Background: Pigment dispersion syndrome affects up to 4% of the white popul ation. it is characterized by the presence of transillumination defects, Kr ukenberg's spindle and dense trabecular meshwork pigmentation. Open-angle g laucoma will develop in as many as 50% of affected patients. In this study we describe the familial occurrence of pigment dispersion syndrome in six N orth American pedigrees and the phenotypic characteristics with respect to pigment dispersion syndrome and glaucoma. Methods: Probands with pigment dispersion syndrome were identified in glauc oma clinics at university eye centres in Ottawa and Durham, NC. Families wi th two or more affected members were evaluated. All willing members in each family underwent a thorough clinical examination and were classified as af fected with pigment dispersion syndrome, suspect or unaffected. The previou s medical records were reviewed to obtain the past medical and ocular histo ry, including risk factors for glaucoma. Results: All six families are white. Three families show at least two gener ations of affected members. Of the 43 subjects examined 58% were women. All 14 affected members showed moderate to heavy trabecular meshwork pigmentat ion and either Krukenberg's spindle or transillumination defects. The affec ted members were also considerably more myopic (mean spherical equivalent f or the right eye -4.72 dioptres) than the suspect group or the unaffected g roup (mean spherical equivalent -0.79 D and +1.19 D respectively) (p less t han or equal to 0.001), and the intraocular pressure was higher for the aff ected than the unaffected group (mean for the right eye 20 mm Hg vs. 16 mm Hg) (p = 0.004). Half of those affected also had open-angle glaucoma. Interpretation: We have identified and phenotypically characterized six Nor th American families with autosomal dominant pigment dispersion syndrome. O ur ultimate goal is to identify the gene(s) that causes this disorder in or der to clarify its molecular etiology and pathophysiology. This may give ri se to a molecular classification of the disease as well as provide the foun dation for genetic testing and new treatment approaches.