Spasmus nutans in identical twins.
D000367:Age Factors; D004200:Diseases in Twins; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D009759:Nystagmus, Pathologic / Q000175:diagnosis*; D011247:Pregnancy; D012075:Remission, Spontaneous; D013035:Spasm / Q000175:diagnosis*; D013577:Syndrome; D014103:Torticollis / Q000175:diagnosis*; D014427:Twins; D014430:Twins, Monozygotic