Opsoclonus-myoclonus (Q84141)

Opsoclonus-myoclonus (OM) is an autoimmune disorder of eye movements characterised by opsoclonus (involuntary unpredictable rapid eye movements [saccades] without inter-saccadic intervals), myoclonus (brief involuntary twitches). Ataxia is often present and while MRI is usually normal, spinal fluid may be inflammatory. OM may be paraneoplastic, post-infectious or idiopathic autoimmune. Paraneoplastic OM in children associates with neuroblastoma, while in adults breast and small-cell-lung cancers are most common. Most do not have an accompanying neural autoantibody, but an exception is the anti-neuronal nuclear antibody type 2 [ANNA-2 or anti-Ri] which is associated with breast, lung and gynaecological cancers.