Inheritance of open-angle glaucoma in the Barbados Family Study

The majority of genetic studies on open-angle glaucoma (OAG) have been cond ucted in primarily white populations, with investigations of inheritance pa tterns largely based on self-reported information. The Barbados Family Stud y of Open-Angle Glaucoma (BFSG) is the first study to investigate the trans mission pattern(s) for OAG in a predominantly black population, based on st andardized examinations. Each BFSG participant received a comprehensive exa mination including anthropometric and other measurements, best-corrected vi sual acuity, perimetry, tonometry, lens gradings, fundus photography, venip uncture, an extensive interview including ocular, medical and family histor y information and a comprehensive ophthalmologic evaluation. Conservative c riteria were used to define glaucoma status, including the presence of both visual field defects and optic disc damage. The study included 207 OAG-aff ected probands (median age: 68 years) and 1,056 of their relatives (median age: 47 years). Among the relatives examined 10% (n = 106) had OAG and 13% (n = 141) had probable OAG. Segregation analyses were performed to determin e the mode of inheritance for glaucoma in these families. The results indic ate that transmission of OAG or probable OAG is most likely due to a major codominant gene. Both age and gender are shown to be significant factors as well; with an increase in risk being associated with each year of age over 54 years and an increase in risk for all ages and genotypes observed in ma les. These analyses do not, however, preclude the possible existence of an environmental component or other genetic determinants in OAG. Further evide nce for the existence of a major gene may be obtained by additional follow- up of the relatively young cohort of relatives, as well as ongoing linkage analyses. (C) 2001 Wiley-Liss, Inc.