Introduction

IgLON5 is an immunoglobulin-like cell adhesion molecule that is widely expressed in the central nervous system (CNS). Autoimmune targeting of this molecule has been associated with heterogeneous waking and sleep neurologic disorders including gait instability, movement disorders, abnormal eye movements, bulbar symptoms and signs, neuropsychiatric symptoms, dysautonomia, peripheral nervous system disorders, and abnormal oneiric behaviors during sleep with symptomatic REM sleep behavior disorder (RBD), sleep apnea, and sleep-related stridor.

Objective

We present a case of a 72 year old male with IgLON5 autoimmune encephalitis.

History

A 72-year-old man with a history of obstructive sleep apnea sought care for chronic choreiform movements, memory impairment and hallucinations, gait ataxia, urinary dysfunction, and abnormal nocturnal behaviors that evolved over 2 years. Choreiform movements were nearly constant while awake, vanished during sleep, and predominantly involved the lower extremities and trunk. 

Management

The patient was treated with melatonin 6 mg at bedtime with improvement in dream enactment behaviors. A therapeutic trial of intravenous methylprednisolone 1 g weekly for 3 months, together with mycophenolate mofetil 1 g twice daily, was followed by improvement in memory, confusion, and hallucinations, chorea, bladder dysfunction, and sleep quality. At 2 year follow-up, choreiform movements had greatly improved, dream enactment had resolved, and gait ataxia was markedly improved.

Conclusion

IgLON5 autoimmunity syndrome was initially reported to involve an invariably poor prognosis, but more recent evidence has suggested the possibility for improvement with timely diagnosis and an individualized plan for immunotherapy, which in our case occurred following pulsed methylprednisolone and mycophenolate mofetil.