Objective:

Background:

IgLON5 autoimmunity was previously described with sleep disorder, rhombencephalopathy, vocal cord paresis, progressive-supranuclear-palsy-like syndrome, and recently motor-neuron-disease (MND)-like syndrome. Although diaphragmatic paralysis has been known as a presenting symptom of degenerative (MND) but has never been reported with IgLON5 autoimmunity.

Design/Methods:

Case report

Results:

A 67-year-old man with obstructive sleep apnea and history of vocal cord paralysis 11 years ago, presented with 2-year history of dream enactment behavior, progressive dyspnea and orthopnea. The symptoms became more noticeable and rapidly progressive in the past 10 months. Initially, he felt shortness of breath during the daytime when he bent over. Within a few months, he had to sleep on the recliner with a minimal tilt back at night. Neurological examination demonstrated moderate right facial weakness, mild weakness of interossei muscles of right hand, and triceps. Deep tendon reflexes were marginally brisk without Babinski sign. Sensory examination was normal. Occasional fasciculation was noted in deltoid region. Right upper extremity electromyography was normal. Diaphragmatic ultrasound showed no diaphragmatic expansion during inspiration. Ultrasound-guided electromyography of diaphragm and phrenic nerve conduction study showed no phrenic nerve response on the right, and markedly reduced amplitude of diaphragmatic compound motor action potential on the left side. Brain MRI and cervical spine was essentially unremarkable. Blood work showed normal vitamin B12, creatinine kinase and monoclonal gammopathy screen.  Serological evaluation of neural specific antibodies was remarkable for IgLON5-IgG (titer 1:480). The patient was treated with high-dose methylprednisolone and is scheduled to follow up in autoimmune neurology clinic for outcome assessment.

Conclusions: