CLINICAL-FEATURES OF AUTOSOMAL-DOMINANT CONGENITAL NYSTAGMUS LINKED TO CHROMOSOME 6P12

PURPOSE: To describe the clinical features of a large pedigree with au tosomal dominant congenital nystagmus linked to chromosome 6p12. METHO DS: In a prospective evaluation of 54 living family members in a singl e pedigree, 21 persons were affected with autosomal dominant congenita l nystagmus, and clinical examinations were performed on 14. Selected persons underwent further studies, including electroretinography, scan ning laser ophthalmoscopy, nerve fiber layer studies, visual evoked po tential studies, and eye movement recordings. RESULTS: Among seven aff ected persons whose parents were able to report whether the nystagmus was present congenitally, onset at birth was noted in two persons and between 3 and 6 months in five persons. Best-corrected binocular Snell en visual acuity ranged from 20/30 to 20/100, with a mode of 20/50. St rabismus was present in 14 examined patients (36%). Eye movement recor dings, performed on five persons, included asymmetric pendular (three) , asymmetric pendular combined with dual waveform jerk (one), and unid irectional jerk nystagmus (one).CONCLUSIONS: Autosomal dominant congen ital nystagmus represents a disorder with variable expressivity. While onset is typically during infancy, it can be noted at birth. Intrafam ilial variation in visual acuity, ocular alignment, and nystagmus wave form suggests a role for modifying influences on expression of disease .