Eye movement abnormalities in a case of X-linked dystonia-Parkinsonism (lubag).

Abstract

To the Editor: X-Linked dystonia-Parkinsonism is a rare movement disorder first described in 1976 on the island of Panay in the Philippines (1). Dubbed by local inhabitants as “lubag” for its characteristic twisting movements, it afflicts males in the third to fifth decades (2,3). We describe a man afflicted with lubag who displays eye movement abnormalities that have not been previously reported. A 54-year-old man from the island of Panay, province of Capiz, the Philippines, had writing difficulties secondary to dystonic hand posturing. This was followed by slowly progressive speech difficulties, dystonic limb and trunk movements, cogwheel rigidity, and postural instability (4). When first examined in 1989, he had no ophthalmic symptoms, and ophthalmologic examination then was remarkable only for horizontal saccadic pursuit movements. Over the next seven years, he was treated with 25 mg carbidopa/250 mg levodopa three times daily, 100 mg amantadine twice daily, 5 mg selegiline three times daily, 4 mg trihexyphenidyl three times daily, and 5 mg bromocriptine three times daily. Examination in 1996 disclosed worsening of his dystonia. Although he still had no ophthalmic symptoms, he now had markedly abnormal eye movements. In straight-ahead gaze, his eyes were aligned and there were no saccadic intrusions. Pursuit was saccadic, as before. Horizontal gaze amplitude was normal, but both eyes displayed marked limitation of upward and downward gaze, estimated as 30% and 40% of normal range, respectively. Both upper lids were retracted. Saccades were slow in all directions; optokinetic nystagmus in the horizontal and vertical planes was symmetrical. Vestibuloocular reflexes by doll's eye maneuver were intact. The remainder of the ophthalmologic examination was normal. Ocular disturbances have not previously been reported in lubag, although their presence parallels those found in other movement disorders such as Parkinson disease and Huntington disease (5,6). In particular, the patient's eye movement abnormalities, with the primary exception of the absence of square wave jerks on primary gaze, bear a strong resemblance to those found in progressive supranuclear palsy (7). Although progressive supranuclear palsy neuropathology includes brainstem involvement (7), autopsy studies in lubag patients have shown atrophy of the caudate nucleus and putamen (2,8). In one case of lubag with myoclonus (9), it was suggested that extrastriatal structures may have been affected, but no other areas have specifically been implicated in the pathogenesis of this disease. In this case, the patient's marked supranuclear ocular disturbances appear consistent with brainstem deficits. Daniel D. Esmaili MD Richard A. Shubin MD Cheryl H. Waters, MD Alfredo A. Sadun, MD, PhD