OBJECTIVE: To explore clinical and genetic features of a pedigree affected with autosomal recessive neuromyotonia and axonal neuropathy (NMAN). METHODS: For the proband and her parents, clinical data was collected, genomic DNA was extracted from peripheral blood samples. Triplet primed-PCR was carried out to detect dynamic mutation of DMPK and ZNF9 genes, which are responsible for myotonic dystrophy, by capillary electrophoresis. High-throughput sequencing was used to screen variants of candidate genes for Mendelian disorders involving the nervous system. Candidate variants were confirmed by Sanger sequencing. The genotype of the variant was determined in the parents and 100 healthy controls. Pathogenicity of the variant was assessed by ACMG criterion. RESULTS: Mutation of DMPK and ZNF9 genes was excluded. DNA sequencing has identified a homozygous missense variant (c.335C>T, p.R119W) in the HINT1 gene. Both parents were found to carry the variant. The same variant was not found among the healthy controls. According to the ACMG criterion, the missense variant was classified as a pathogenic variant. CONCLUSION The c.335C>T (p.R119W) of the HINT1 gene probably underlie the disease in this pedigree. Above finding provided further evidence for the connection between HINT1 and NMAN and enriched the mutation spectrum of HINT1 gene.
Female ; Genotype ; Homozygote ; Humans ; Isaacs Syndrome ; genetics ; Nerve Tissue Proteins ; genetics ; Pedigree

Autoimmune encephalitis causes subacute deficits of memory and cognition, often followed by suppressed level of consciousness or coma. A careful history and examination may show early clues to particular autoimmune causes, such as neuromyotonia, hyperekplexia, psychosis, dystonia, or the presence of particular tumors. Ancillary testing with MRI and EEG may be helpful for excluding other causes, managing seizures, and, rarely, for identifying characteristic findings. Appropriate autoantibody testing can confirm specific diagnoses, although this is often done in parallel with exclusion of infectious and other causes. Autoimmune encephalitis may be divided into several groups of diseases: those with pathogenic antibodies to cell surface proteins, those with antibodies to intracellular synaptic proteins, T-cell diseases associated with antibodies to intracellular antigens, and those associated with other autoimmune disorders. Many forms of autoimmune encephalitis are paraneoplastic, and each of these conveys a distinct risk profile for various tumors. Tumor screening and, if necessary, treatment is essential to proper management. Most forms of autoimmune encephalitis respond to immune therapies, although powerful immune suppression for weeks or months may be needed in difficult cases. Autoimmune encephalitis may relapse, so follow-up care is important.
Anti-N-Methyl-D-Aspartate Receptor Encephalitis ; Antibodies ; Cognition ; Coma ; Consciousness ; Diagnosis* ; Dystonia ; Electroencephalography ; Encephalitis* ; Follow-Up Studies ; Isaacs Syndrome ; Magnetic Resonance Imaging ; Mass Screening ; Membrane Proteins ; Memory ; Psychotic Disorders ; Recurrence ; Seizures ; Stiff-Person Syndrome ; T-Lymphocytes

Channelopathies are a heterogeneous group of disorders resulting from the dysfunction of ion channels located in the membranes of all cells and many cellular organelles. These include diseases of the nervous system (e.g., generalized epilepsy with febrile seizures plus, familial hemiplegic migraine, episodic ataxia, and hyperkalemic and hypokalemic periodic paralysis), the cardiovascular system (e.g., long QT syndrome, short QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia), the respiratory system (e.g., cystic fibrosis), the endocrine system (e.g., neonatal diabetes mellitus, familial hyperinsulinemic hypoglycemia, thyrotoxic hypokalemic periodic paralysis, and familial hyperaldosteronism), the urinary system (e.g., Bartter syndrome, nephrogenic diabetes insipidus, autosomal-dominant polycystic kidney disease, and hypomagnesemia with secondary hypocalcemia), and the immune system (e.g., myasthenia gravis, neuromyelitis optica, Isaac syndrome, and anti-NMDA [N-methyl-D-aspartate] receptor encephalitis). The field of channelopathies is expanding rapidly, as is the utility of molecular-genetic and electrophysiological studies. This review provides a brief overview and update of channelopathies, with a focus on recent advances in the pathophysiological mechanisms that may help clinicians better understand, diagnose, and develop treatments for these diseases.
Ataxia ; Bartter Syndrome ; Brugada Syndrome ; Cardiovascular System ; Channelopathies* ; Diabetes Insipidus, Nephrogenic ; Diabetes Mellitus ; Endocrine System ; Epilepsy, Generalized ; Genetics ; Hypoglycemia ; Hypokalemic Periodic Paralysis ; Immune System ; Ion Channels ; Isaacs Syndrome ; Long QT Syndrome ; Membranes ; Migraine with Aura ; Myasthenia Gravis ; Nervous System ; Neuromyelitis Optica ; Organelles ; Polycystic Kidney Diseases ; Respiratory System ; Seizures, Febrile

BACKGROUND: Acquired neuromyotonia (NMT) forms part of the spectrum of acquired peripheral nerve hyperexcitability syndrome, and is thought to be caused by antibodies to voltage-gated potassium channels (VGKC). Exertional weakness is unusual unless autoimmune myasthenia gravis (MG) is superimposed. CASE REPORT: A case of acquired NMT accompanied by exertional weakness without coexistence of seropositive MG is reported herein. CONCLUSIONS: Clinical and electrophysiological observations suggest that the cholinergic overactivity in NMT can compromise the safety factor sufficiently to cause a defect in neuromuscular junction transmission.
Antibodies ; Isaacs Syndrome* ; Myasthenia Gravis ; Neuromuscular Junction ; Peripheral Nerves ; Potassium Channels, Voltage-Gated

We report on an anesthetic experience with a 74-year-old female with Isaacs' syndrome, who underwent elective surgery for open rotator cuff repair. Isaacs' syndrome is a rare peripheral motor neuron disorder with clinical manifestations such as involuntary muscle twitching, cramps, mild weakness and increased sweating. To avoid prolonged neuromuscular blockade, the patient was observed with neuromuscular monitoring during total intravenous anesthesia with propofol, remifentanil, and atracurium. No adverse events were observed during the anesthetic management, and the patient recovered smoothly from the neuromuscular blockade. We describe the clinical characteristics of Isaacs' syndrome and its specific considerations in anesthesia.
Anesthesia ; Anesthesia, Intravenous ; Atracurium ; Female ; Humans ; Isaacs Syndrome ; Motor Neurons ; Muscle Cramp ; Muscle, Smooth ; Neuromuscular Blockade ; Neuromuscular Monitoring ; Piperidines ; Propofol ; Rotator Cuff ; Sweat ; Sweating

No abstract available.
Diplopia ; Humans ; Isaacs Syndrome ; Neoplasm Metastasis ; Orbit

Isaacs' syndrome is a rare and heterogeneous syndrome of continuous muscle fiber activity that originates from peripheral nerves. We report a 56-year-old male patient who showed symptoms of Isaacs' syndrome after the removal of a malignant thymoma. Needle electromyography revealed spontaneously occurring repetitive myokymic discharge in the affected muscles. Acetylcholine receptor (AChR) antibodies were significantly elevated, but clinical and electrophysiologic findings did not indicate the presence of myasthenia gravis. We deduce that in Isaacs' syndrome, raised AChR antibodies may facilitate rather than inhibit cholinergic action.
Acetylcholine ; Antibodies ; Electromyography ; Humans ; Isaacs Syndrome ; Male ; Middle Aged ; Muscles ; Myasthenia Gravis ; Needles ; Peripheral Nerves ; Thymoma

A 52-year-old woman developed episodic diplopia during a period of six months. Between the episodes, depression of the right eye was mildly impaired and lid lag was evident in the right eye on downward gaze. On resuming the primary position after prolonged leftward gaze, she developed a right esotropia and limitation of abduction, elevation, and depression in the right eye. Lid lag may be a sign suggesting oculomotor neuromyotonia in patients with episodic diplopia. The isolated lid lag without lid retraction suggests primary aberrant oculomotor regeneration as a mechanism of this phenomenon.
Depression ; Diplopia ; Esotropia ; Female ; Humans ; Isaacs Syndrome* ; Middle Aged ; Oculomotor Nerve ; Regeneration

Neuromyotonia, or Isaacs' syndrome, consists of continuous muscle fiber activity caused by hyperexcitability of the peripheral nerves. Rarely, these patients also develop CNS symptoms characterized by confusion, insomnia, hallucinations, and agitation. A rare disease consisting of neuromyotonia, autonomic symptoms, and CNS dysfunction is called Morvan's syndrome. We report a 24-year-old man who presented with insomnia, malaise, anorexia, hyperhidrosis, palpitation and myokymia in both the lower extremities. The pathomechanism of Morvan's syndrome is related to the voltage-gated K+ channel (VGKC) antibodies.
Anorexia ; Antibodies ; Dihydroergotamine ; Hallucinations ; Humans ; Hyperhidrosis ; Isaacs Syndrome ; Lower Extremity ; Myokymia ; Peripheral Nerves ; Rare Diseases ; Sleep Initiation and Maintenance Disorders ; Young Adult

Ocular neuromyotonia (ONM) is an episodic involuntary contraction of one or more extraocular muscles, resulting from spontaneous neural discharges of ocular motor nerves. Previous radiation therapy to pituitary or other juxtasellar tumor and vascular compressions are the most common reported causes of ONM. We report one unique case of ONM involving the abducens nerve without any other organic brain lesion and prior radiation therapy.
Abducens Nerve ; Brain ; Isaacs Syndrome* ; Muscles