THE OCULAR PHENOTYPE OF THE BARDET-BIEDL SYNDROME - COMPARISON TO NON-SYNDROMIC RETINITIS-PIGMENTOSA

Purpose: To investigate 20 patients affected with Bardet-Biedl (BB) sy ndrome and compare them to an age-matched group of 70 non-syndromic pa tients with retinitis pigmentosa (RP) to identify hallmarks peculiar t o the BE phenotype. Methods: Patients were examined clinically and wit h functional tests (color vision, kinetic perimetry, electroretinograp hy, ocular motility tests). Fundus findings were numerically graded fo r statistical purposes. Results: Recurrent ocular features in BE patie nts were early and severe reduction of visual acuity, constantly alter ed color vision, high incidence of strabismus and nystagmus, mild-to-s evere atrophic changes of the optic disc, and frequently absent or min imal pigmentary retinal changes. Visual acuity was more closely correl ated to optic disc than to macular conditions. These findings were rem arkably different from non-syndromic RP. Conclusions: This investigati on further suggests that retinopathy in BE syndrome has features disti nctive from those in non-syndromic RP. The early occurrence of optic d isc atrophy in the BE syndrome, even in those patients with healthy ma culas, suggests that optic atrophy could often be primary in nature an d might play a major role in decreasing central vision in BE patients. Variability of some findings is in line with the documented heterogen eity of the BE syndrome.