Electrophysiological and eye-movement abnormalities in children with the Bardet-Biedl syndrome.

We investigated 17 patients with clinical features of Bardet-Biedl syndrome by electroretinogram (ERG), visual-evoked potentials (VEP), and electro-oculographic (EOG) eye movement assessment. The ERGs were grossly abnormal in 16 cases. Pattern VEPs were generally well preserved, but showed a tendency to increase in latency and decrease in amplitude with age. These results confirm other reports that the retinopathy appears to be a progressive rod-cone dystrophy initially affecting mainly extramacular areas but involving the macula at later stages. Seven of 11 patients showed abnormalities of either optokinetic nystagmus, vestibulo-ocular reflex, or both. These eye-movement abnormalities have not been reported previously, and are further evidence of central nervous system involvement in this syndrome.