PT - JOURNAL ARTICLE AU - R V Abadi AU - E Pascal TI - Ocular motor behaviour of monozygotic twins with tyrosinase negative oculocutaneous albinism. AID - 10.1136/bjo.78.5.349 DP - 1994 May 01 TA - British Journal of Ophthalmology PG - 349--352 VI - 78 IP - 5 4099 - http://bjo.bmj.com/content/78/5/349.short 4100 - http://bjo.bmj.com/content/78/5/349.full SO - Br J Ophthalmol1994 May 01; 78 AB - The involuntary nystagmus movements of 16-year-old monozygotic twins with tyrosinase negative oculocutaneous albinism were examined. On primary gaze both girls exhibited bilateral conjugate horizontal nystagmus, a jerk with extended foveation waveform, and similar frequencies (2.0 Hz:1.9 Hz), although the fast phases were in opposite directions. The mean amplitudes differed markedly (6.8 degrees:3.7 degrees), as did the position of the null zones (+20 degrees to +30 degrees:-25 degrees to -35 degrees) and the widths of the neutral zones (-25 degrees to +20 degrees:-25 degrees to -35 degrees). Since the twins have identical genotypes these differences must have arisen from other sources.