Ocular motor dysfunction in Lesch-Nyhan disease

Eye movements were assessed in 22 patients with varying degrees of hypoxant hine-guanine phosphoribosyltransferase deficiency. Ocular motility was clin ically normal in seven patients with moderate enzyme deficiency but grossly abnormal in 15 patients with severe enzyme deficiency. In patients with se vere deficiency, fixation was interrupted by frequent unwanted saccades tow ard minor visual distractions. Voluntary saccades were associated with an i nitial head movement and/or eyeblink in all of these patients. When head mo tion was prevented, voluntary saccades were often delayed and sometimes abs ent. In contrast, saccade speed, reflexive saccades, and other reflexive ey e movements appeared clinically normal, Four patients with severe enzyme de ficiency also experienced mild blepharospasm, and two had ocular ties. Thes e disturbances of ocular motility are consistent with dysfunction of the ba sal ganglia or its connections with ocular motor centers in the prefrontal cortex or midbrain. (C) 2001 by Elsevier Science Inc, All rights reserved.