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

Abstract

To investigate the nystagmus of twin brothers presenting with spasmus nutans later diagnosed as Bardet-Biedl syndrome. The twins presented at the age of 14 months with a presumed diagnosis of spasmus nutans. They were followed clinically and with quantitative electro-oculographic eye movement recordings until the age of 6 years. Polydactyly, truncal obesity, mild delay in cognitive development, visual acuity of 20/100, attenuated retinal vessels and pale disks, and bilaterally almost extinguished scotopic and photopic electroretinograms were found in both brothers. They had fine, fast, pendular, disconjugate, intermittent, oblique nystagmus. No head nodding was observed. As described in patients with other retinal diseases such as achromatopsia and congenital stationary night blindness, nystagmus of patients with Bardet-Biedl syndrome can mimic spasmus nutans.