Nystagmus mimicking spasmus nutans as the presenting sign of Bardet-Biedl syndrome

PURPOSE: To investigate the nystagmus of twin brothers presenting with spas mus nutans later diagnosed as Bardet-Biedl syndrome. METHODS: The twins presented at the age of 14 months with a presumed diagno sis of spasmus nutans, They were followed clinically and with quantitative electro-oculographic eye movement recordings until the age of 6 years. RESULTS: Polydactyly, truncal obesity, mild delay in cognitive development, visual acuity of 20/100, attenuated retinal vessels and pale disks, and bi laterally almost extinguished scotopic and photopic electroretinograms were found in both brothers. They had tine, fast, pendular, disconjugate, inter mittent, oblique nystagmus. No head nodding was observed. CONCLUSION: As described in patients with other retinal diseases such as ac hromatopsia and congenital stationary night blindness, nystagmus of patient s with Bardet-Biedl syndrome can mimic spasmus nutans. (C) 1999 by Elsevier Science Inc. All rights reserved.