Biological phase separation refers to the liquid-liquid phase separation of biomolecules such as proteins in cells. Phase separation is driven by low-complexity domains of phase-separating proteins and strictly controlled by regulatory factors. Phase separation has also been found to be disrupted by genetic abnormalities. Abnormal aggregates of causative proteins accumulate in many neuromuscular diseases. In recent years, it has become clear that phase separating proteins are associated with neuromuscular diseases, and that abnormalities in the regulation of phase separation leads to the formation of aggregates. Gains in our knowledge of biological phase separation is gradually elucidating the pathogenesis of neuromuscular diseases.

The differential diagnosis of inflammatory and non-inflammatory myelopathy can be challenging. Clinical information such as age, gender, speed of onset and progression, systemic symptoms, spinal cord and brain MRI, autoantibodies, and cerebrospinal fluid findings are necessary. The speed of onset is particularly important for differentiation. Inflammatory myelopathy typically follows an acute/subacute course, while spinal cord infarction presents with a hyperacute course, and intramedullary tumors often have a chronic progressive course. Spinal dural arteriovenous fistula usually shows a chronic progressive course, but it can present with fluctuating symptoms in the early stages and may appear as an acute onset. It is essential to definitively exclude compressive myelopathy for the diagnosis of inflammatory myelopathy. Even if a definitive diagnosis cannot be made, regular reevaluation during treatment is necessary.

Using the Japanese version of the Impact of Migraine on Partners and Adolescent Children (IMPAC) and Family Question prepared based on IMPAC, we investigated the impact of migraine on family members from the perspectives of both patients and their family members. Our results showed that migraine had an impact on the family members living with the patients in Japan as well, and the perception of migraine differed partially between patients and their family members. We also found that the Japanese version of the IMPAC showed a correlation with existing instruments to evaluate impact of migraine, indicating its validity. The application of this study’s findings in clinical practice could help alleviate the disease burden of migraine on patients and their family members.

A 62-year-old man was admitted to our hospital for acute bilateral blindness two days after a head injury. Hemorrhagic cerebellar infarction was found on the initial MRI, and peripheral arteries were poorly visualized on MRA. On the follow-up MRA nine days later, peripheral arteries were clearly depicted. These imaging findings suggested reversible cerebral vasoconstriction syndrome (RCVS). We started steroid pulse therapy for suspected optic neuritis with no clear response. The initial fundoscopic examination revealed no abnormalities in the optic disc, but optic nerve atrophy developed one month later. Based on the course of events, we diagnosed the patient with posterior ischemic optic neuropathy triggered by RCVS.

An 84-year-old man was diagnosed with anti-acetylcholine receptor (AChR) antibody-positive ocular myasthenia gravis (OMG) at the age of 77 and received treatment. The patient was referred to our department with swelling and pain in his right upper arm, which had spread to other limbs. His serum anti-AChR antibody and creatine kinase levels were elevated, and MRI of the limbs displayed signal changes suggesting inflammation in the several muscles. Despite showing no sign of thymoma, he was positive for serum anti-titin and anti-Kv1.4 antibodies. We performed a muscle biopsy, which led to a diagnosis of inflammatory myopathy (IM). IM associated with OMG is relatively mild. Age-related immune dysregulation may cause both OMG and IM. Evaluation of disease activity with serum anti-AChR antibody levels, and assessment of prognosis with examining anti-striational antibodies are necessary for appropriate management of IM associated with MG.

A 19-year-old female, normal at birth, grew up without neck movement when getting up. She needed a handrail to climb stairs since the age of 10 years old, and walked slowly since the age of 16 years old. Neurological examination revealed loss of deep tendon reflexes, decreased vibratory sensation, weakness of distal muscles of the lower extremities, and weakness of mainly cervical trunk muscles suspected to be due to myopathy. Nerve conduction studies suggested axonal polyneuropathy, and needle EMG showed short duration MUP, myotonic discharge, and rimmed vacuoles on muscle biopsy. Genetic analysis revealed a previously reported pathological mutation (p.P209L, heterozygous) in Bcl2-Associated Athanogene 3 (BAG3), and a diagnosis of MFM6 was made. P209L is a poor prognosis myopathy that develops in childhood and is associated with cardiomyopathy. P209L is a solitary myopathy associated with axonal neuropathy and characterized by apex foot contracture and weak neck to trunk flexion. This disease is suspected in young-onset neuromyopathy.

A 25-year-old male presented with clonic seizures three days following a fever. The patient developed status epilepticus and required mechanical ventilation and intravenous anesthesia. The patient’s epileptic seizures persisted despite administering intravenous anesthesia and multiple anti-epileptic drugs. The clinical presentation in this case, without pre-existing relevant neurological disorder and an active structural, toxic, or metabolic cause in the acute phase, was compatible with new-onset refractory status epilepticus (NORSE). After immunotherapy, including intravenous methylprednisolone, plasma exchange, and intravenous immunoglobulin therapy, the epileptic discharge on electroencephalogram (EEG) decreased gradually, and mechanical ventilation was discontinued. Neversless the final outcome was poor. The patient’s condition was finally diagnosed as cryptogenic NORSE. The IL-6 levels in the cerebrospinal fluid showed a significant increase between day 6 and 11 after onset, during which time there was a rapid escalation in seizure frequency on EEG. Considering this, IL-6 may be involved in the process of seizure exacerbation.