Channelopathies Quiz

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Questions and Answers

What is the significance of maternal transmission in congenital myotonic dystrophy?

It indicates that CDM primarily arises from mutations inherited from the mother.

What mutation is associated with Inherited (Primary) Erythromelalgia and what are its symptoms?

The mutation in SCN9A is associated with Inherited Erythromelalgia, causing episodes of redness and swelling in hands and feet, along with burning pain.

Describe a clinical feature of the early congenital form of DM1.

Clinical features include respiratory failure, poor feeding, and hypotonia.

How does the CTG expansion in the DMPK gene relate to DM1 severity?

Longer CTG expansions result in an earlier onset and more severe symptoms of DM1. Signup and view all the answers

What type of seizures are characterized by bizarre hypermotor behavior during nocturnal episodes and which mutation is responsible?

Autosomal-Dominant Nocturnal Frontal Lobe Epilepsy features nocturnal frontal lobe seizures with bizarre hypermotor behavior, caused by nicotinic receptor mutations. Signup and view all the answers

What role does mexiletine play in the treatment of myotonic dystrophies?

Mexiletine is used to alleviate myotonia, improving muscle relaxation after contractions. Signup and view all the answers

Which condition is associated with SCN2A1 mutation and what defines its onset timeline?

Benign Familial Infantile-Neonatal Seizures are associated with SCN2A1 mutation and occur slightly older than typical benign neonatal seizures. Signup and view all the answers

What distinguishes DM2 from DM1 in terms of genetic mutation?

DM2 is caused by a CCTG expansion in the CNBP gene, whereas DM1 is due to a CTG expansion in the DMPK gene. Signup and view all the answers

What is a characteristic symptom of myotonia in DM2?

A characteristic symptom is myotonia of eye closure, which can cause stiffness. Signup and view all the answers

What is Congenital Indifference to Pain (CIP) and what mutation causes it?

Congenital Indifference to Pain (CIP) is characterized by insensitivity to pain, associated with a mutation in SCN9A leading to loss of function. Signup and view all the answers

Identify one diagnostic method for DM1.

Genetic testing is a primary diagnostic method for DM1. Signup and view all the answers

What triggers the pain episodes in Paroxysmal Extreme Pain Disorder, and what mutation is involved?

Paroxysmal Extreme Pain Disorder is triggered by stimulation in the perirectal region, and it is caused by a mutation in SCN9A. Signup and view all the answers

What is the common treatment for Inherited (Primary) Erythromelalgia, and how do sodium channel blockers affect its symptoms?

Treatment for Inherited Erythromelalgia includes sodium channel blockers like lidocaine, mexiletine, or carbamazepine, which can help alleviate symptoms. Signup and view all the answers

What is the warm-up phenomenon associated with DM2?

The warm-up phenomenon refers to reduced myotonic stiffness after repeated contractions. Signup and view all the answers

What are the key clinical features of Familial Hemiplegic Migraine type 1 (FHM1)?

FHM1 is associated with severe unilateral headache, ataxia, coma, and delayed cerebral edema after minor head injury. Signup and view all the answers

Which genetic condition is associated with mutations in GABA receptors and what is its characteristic seizure type?

Childhood Absence Epilepsy is associated with mutations in GABA receptors and is characterized by absence seizures. Signup and view all the answers

Describe the difference between Episodic Ataxia type 1 and type 2 in terms of precipitating factors and symptoms.

EA type 1 episodes are brief and often triggered by emotional outbursts and sudden movements, while EA type 2 episodes last longer and can be induced by stress or exercise. Signup and view all the answers

What diagnostic methods are used to distinguish between the two types of episodic ataxia?

EMG is used to detect myokymia in EA type 1, while MRI showing cerebellar vermis atrophy is used for EA type 2. Signup and view all the answers

What are the common environmental triggers for pain episodes in Paroxysmal Extreme Pain Disorder?

Common triggers for pain episodes in Paroxysmal Extreme Pain Disorder include bowel movements, contact in the perianal region, eating, or sudden temperature changes. Signup and view all the answers

What genetic mutation is associated with Spinocerebellar Ataxia type 6 (SCA6)?

SCA6 is associated with triplet repeats in the CACNA1A gene. Signup and view all the answers

In what way do symptoms of SCA6 differ from other forms of ataxia regarding spasticity and cranial nerve involvement?

Spasticity and cranial nerve neuropathies are not common in SCA6, unlike other forms of ataxia. Signup and view all the answers

What is the primary treatment for Familial Hemiplegic Migraine and what is its mechanism?

Acetazolamide is the primary treatment, functioning as a carbonic anhydrase inhibitor to stabilize neuronal excitability. Signup and view all the answers

What are the general features of myotonic dystrophy and its inheritance pattern?

Myotonic dystrophy features progressive muscle weakness and myotonia, with autosomal dominant inheritance. Signup and view all the answers

Why are autonomy nervous system abnormalities significant when evaluating peripheral neuropathy symptoms?

The absence of autonomic nervous system abnormalities suggests a limited peripheral nerve involvement, distinguishing between types of neuropathy. Signup and view all the answers

What is the age of onset for dominant gene defect myopathy?

Infancy to early childhood. Signup and view all the answers

In recessive gene defect myopathy, what type of muscle changes can occur?

Occasional muscle wasting and weakness can occur late, but hypertrophy of leg muscles is frequent. Signup and view all the answers

How does myotonia present in dominating gene defect compared to recessive gene defect?

Dominant myotonia exhibits generalized stiffness that improves with exercise, while recessive myotonia includes transient weakness after relaxation. Signup and view all the answers

What type of therapy is recommended for managing symptoms associated with both dominant and recessive myopathy?

Exercise and antimyotonia therapy (mexiletine) are recommended. Signup and view all the answers

What distinguishing feature characterizes acetazolamide-responsive sodium channel myotonia?

It features paradoxical eyelid myotonia, where eyelids get stuck after crying. Signup and view all the answers

What is a common complication regarding exercise for patients with myotonia fluctuans?

Patients may experience exercise-induced delayed onset myotonia after a period of rest following vigorous exercise. Signup and view all the answers

What treatment option is specifically used for managing acetazolamide-responsive sodium channel myotonia?

Acetazolamide is used for managing this condition. Signup and view all the answers

What diagnostic methods are utilized for myotonic disorders as mentioned in the content?

Genetic testing and EMG (electromyography) are used for diagnosis. Signup and view all the answers

What are the main dietary recommendations for managing acute attacks of periodic paralysis?

A low sodium/low carb diet and supplemental doses of potassium chloride taken 2-4 times a day. Signup and view all the answers

How is hypokalemic periodic paralysis diagnosed during an attack?

Diagnosis involves electrolyte monitoring and ECG during an attack. Signup and view all the answers

What is a significant genetic factor associated with Andersen-Tawil syndrome?

A mutation in the KCNJ2 gene, which encodes potassium channels, is a significant factor. Signup and view all the answers

What triggers are known to precipitate attacks in thyrotoxic periodic paralysis?

Attacks can be triggered by lack of sleep, hot weather, and excessive physical activity. Signup and view all the answers

What treatment options are available for managing cardiac arrhythmias in periodic paralysis?

Treatment options include acetazolamide and dichlorphenamide to stabilize potassium levels. Signup and view all the answers

Why is muscle biopsy not usually necessary in the diagnosis of periodic paralysis?

A muscle biopsy is rarely required as other diagnostic methods are typically sufficient. Signup and view all the answers

What is an important pathophysiological feature of Andersen-Tawil syndrome?

It is characterized by periodic paralysis, long QT syndrome, and ventricular dysrhythmias. Signup and view all the answers

What role does acetazolamide play in the treatment of periodic paralysis?

Acetazolamide helps to produce metabolic acidosis and works on skeletal muscles to stabilize potassium flux. Signup and view all the answers

Study Notes

### Channelopathies

Channelopathies are disorders that affect ion channels in the cell membrane.
They are often caused by mutations in genes that code for ion channels.
They can cause a variety of problems, including muscle disorders, epilepsy, and pain syndromes.
Typically inherited in an autosomal dominant pattern unless otherwise stated.
Some chanellpathies cause seizures, many are treatable with medications that modulate sodium or potassium channels.

### Epilepsy

Ohtahara syndrome is a severe form of epilepsy that often begins in the first few days of life.
Ohtahara syndrome is characterized by refractory spasms, tonic-clonic and myoclonic seizures, and developmental delay.
Ohtahara syndrome is associated with mutations in genes that code for ion channels, including sodium channel, potassium channel and chloride channel genes.
Ohtahara syndrome is treatable with sulfonylurea medication (glibenclamide) which can improve diabetes, developmental outcome, and seizures.
Autosomal-Dominant Nocturnal Frontal Lobe Epilepsy is characterized by nocturnal frontal lobe seizures and waking up with bizarre hypermotor behaviour such as spinning, thrashing, rocking.
Autosomal-Dominant Nocturnal Frontal Lobe Epilepsy is caused by mutations in nicotinic receptor genes.
Autosomal-Dominant Nocturnal Frontal Lobe Epilepsy is treatable with carbamazepine and phenytoin.
Benign Familial Infantile-Neonatal Seizures is similar to benign neonatal seizures but the age of onset is slightly older.
Benign Familial Infantile-Neonatal Seizures is associated with mutations in SCN2A1 gene.
Childhood Absence Epilepsy is caused by mutations in GABA receptors (GABRA1/GABRA2), chloride channels (CLCN2) and calcium channel (CACNA1H).
Childhood Absence Epilepsy is a polygenic disorder (meaning it can be caused by mutations in multiple genes).
Juvenile Myoclonic Epilepsy is caused by mutations in GABA receptors (GABRA1/GABRD), calcium channels (CACNB4) and chloride channels (CLCN2).
Juvenile Myoclonic Epilepsy is a polygenic disorder.

### Pain Syndromes

Inherited (Primary) Erythromelalgia is caused by mutations in SCN9A gene.
Inherited (Primary) Erythromelalgia can cause episodes of redness and swelling of hands and feet, associated with burning pain.
Inherited (Primary) Erythromelalgia can be triggered by mild warmth or exercise.
Inherited (Primary) Erythromelalgia can be treated with sodium channel blockers, such as lidocaine, mexiletine, and carbamazepine.
Paroxysmal Extreme Pain Disorder is caused by mutations in the SCN9A gene.
Paroxysmal Extreme Pain Disorder can cause episodic severe pain, commonly occurring in the perirectal region, but can also involve genitals, limbs, face (periorbital region).
Paroxysmal Extreme Pain Disorder can be triggered by bowel movement, contact in the perianal region, eating or sudden changes in temperature.
Paroxysmal Extreme Pain Disorder is treatable with carbamazepine but not topiramate or gabapentin.
Congenital Indifference to Pain is caused by mutations in the SCN9A gene.
Congenital Indifference to Pain causes insensitivity to pain and sometimes loss of smell.
Congenital Indifference to Pain can be associated with anhidrosis, intellectual disability, hypotonia.
Congenital Indifference to Pain can be diagnosed with neurophysiological testing.

Migraines and Ataxia Syndromes

Familial Hemiplegic Migraines are caused by mutations in genes that code for ion channels.
Familial Hemiplegic Migraines type 1 (FHM1) is caused by mutations in the CACNA1A gene (calcium channel).
Familial Hemiplegic Migraines type 1 (FHM1) can lead to ataxia and coma and delayed cerebral edema after minor head injury.
Familial Hemiplegic Migraines type 2 (FHM2) is caused by mutations in the ATP1A2 gene (sodium-potassium ATPase) or the PRRT2 gene.
Familial Hemiplegic Migraines type 3 (FHM3) is caused by mutations in the SCN1A gene (sodium channel).
Familial Hemiplegic Migraines usually present in the first or second decade of life with severe headaches, often unilateral, with unilateral weakness, paresthesia or hemianopsia.
Familial Hemiplegic Migraines can be diagnosed with MRI, which can show cerebellar atrophy, and an EEG during an event.
**Familial Hemiplegic Migraines ** can be treated with acetazolamide (Diamox), verapamil (calcium channel blocker), and flunarizine.
Episodic Ataxia is characterized by intermittent periods of ataxia, ataxia can be triggered by exercise, stress or emotional outburst.
Episodic Ataxia type 1 is caused by mutations in the KCNA1 gene (potassium channel).
Episodic Ataxia type 1 is characterized by frequent, brief episodes of ataxia (gait) and slurred speech.
Episodic Ataxia type 1 can be diagnosed with EMG, which can show myokymia.
Episodic Ataxia type 2 is caused by mutations in the CACNA1A gene (calcium channel).
Episodic Ataxia type 2 is characterized by truncal ataxia lasting hours to days.
Episodic Ataxia type 2 can be diagnosed with MRI, which can show cerebellar vermis atrophy.
Episodic Ataxia can be treated with acetazolamide and carbamazepine.
Spinocerebellar Ataxia type 6 is caused by triplet repeats in the CACNA1A gene (calcium channel).
Spinocerebellar Ataxia type 6 is characterized by slowly progressive cerebellar degeneration.
Spinocerebellar Ataxia type 6 is diagnosed with genetic testing.
Spinocerebellar Ataxia type 6 can be treated with supportive care.

Muscle Disorders

Myotonic Dystrophy is a group of inherited disorders that cause muscle weakness, myotonia (difficulty relaxing muscles), and other problems.
Myotonic Dystrophy is inherited in an autosomal dominant pattern.
Myotonic Dystrophy is caused by mutations in genes that code for proteins involved in muscle function.
Myotonic Dystrophy type 1 (DM1) is caused by an abnormal expansion of a CTG repeat in the DMPK gene.
Myotonic Dystrophy type 1 (DM1) can cause a wide range of symptoms, including muscle weakness, myotonia, cataracts, heart problems, and intellectual disability.
The longer the CTG repeat, the more severe and earlier onset of symptoms.
Myotonic Dystrophy type 1 (DM1) can be diagnosed with genetic testing.
Myotonic Dystrophy type 1 (DM1) is treatable with medications, such as mexiletine and quinine, which can help to reduce muscle stiffness and weakness.
Myotonic Dystrophy type 2 (DM2) is caused by an abnormal expansion of a CCTG repeat in the CNBP gene.
Myotonic Dystrophy type 2 (DM2) usually presents in adulthood.
Myotonic Dystrophy type 2 (DM2) is typically milder than DM1.
Myotonic Dystrophy type 2 (DM2) can be diagnosed with genetic testing.
Myotonic Dystrophy type 2 (DM2) can be treated with medications, such as mexiletine and carbamazepine, which can help to reduce muscle stiffness and weakness.
Myotonia Congenita is a group of inherited disorders that cause muscle stiffness and weakness, it is caused by mutations in genes that code for chloride channels in skeletal muscle.
Myotonia Congenita is inherited in an autosomal dominant or autosomal recessive pattern.
There are two main forms of myotonia congenita: Thomsen's disease and Becker's myotonia.
Thomsen's disease is inherited in an autosomal dominant pattern.
Thomsen's disease is characterized by generalized stiffness that improves with exercise.
Thomsen's disease can be diagnosed with EMG.
Thomsen's disease can be treated with medications, such as mexiletine, which can help to reduce muscle stiffness and weakness.
Becker's myotonia is inherited in an autosomal recessive pattern.
Becker's myotonia is characterized by generalized stiffness that improves with exercise.
Becker's myotonia can be diagnosed with EMG.
Becker's myotonia can be treated with medications, such as mexiletine, which can help to reduce muscle stiffness and weakness.
Acetazolamide-responsive Sodium Channel Myotonia (ARSCM) is an inherited disorder that causes muscle stiffness, weakness, and spasms.
Acetazolamide-responsive Sodium Channel Myotonia (ARSCM) is inherited in an autosomal dominant pattern
Acetazolamide-responsive Sodium Channel Myotonia (ARSCM) is caused by mutations in sodium channel genes.
Acetazolamide-responsive Sodium Channel Myotonia (ARSCM) can be diagnosed with EMG.
Acetazolamide-responsive Sodium Channel Myotonia (ARSCM) is treatable with acetazolamide.
Myotonia Fluctuans is a rare inherited disorder that causes muscle stiffness, weakness, and spasms; it is similar to ARSCM but with more fluctuation in symptoms.
Myotonia Fluctuans is inherited in an autosomal dominant pattern.
Myotonia Fluctuans is caused by mutations in sodium channel genes.
Myotonia Fluctuans can be diagnosed with EMG.
Myotonia Fluctuans is treatable with acetazolamide.
Periodic Paralysis is a group of inherited disorders that cause episodes of muscle weakness that can last from a few minutes to several hours.
Periodic Paralysis is caused by mutations in genes that code for proteins involved in muscle function.
There are several types of periodic paralysis, including hypokalemic periodic paralysis (HPP), hyperkalemic periodic paralysis (HYPP), and paramyotonia congenita (PC).
Hypokalemic Periodic Paralysis is caused by mutations in sodium channel genes or calcium channel genes.
Hypokalemic Periodic Paralysis can be diagnosed with blood tests and EMG.
Hypokalemic Periodic Paralysis is treatable with acetazolamide.
Hyperkalemic Periodic Paralysis is caused by mutations in sodium channel genes.
Hyperkalemic Periodic Paralysis can be diagnosed with blood tests and EMG.
Hyperkalemic Periodic Paralysis is treatable with acetazolamide and a low-sodium diet.
Paramyotonia Congenita is caused by mutations in sodium channel genes.
Paramyotonia Congenita can be diagnosed with blood tests and EMG.
Paramyotonia Congenita is treatable with acetazolamide and mexiletine.
Andersen-Tawil Syndrome is a rare genetic disorder that causes periodic paralysis, long QT syndrome, and cardiac arrhythmias.
Andersen-Tawil Syndrome is inherited in an autosomal dominant pattern.
Andersen-Tawil Syndrome is caused by mutations in the KCNJ2 gene (potassium channel).
Andersen-Tawil Syndrome can be diagnosed with ECG monitoring and genetic testing.
Andersen-Tawil Syndrome can be treated with acetazolamide and dichlorphenamide.
Thyrotoxic Periodic Paralysis is a condition that is often sporadic (not inherited).
Thyrotoxic Periodic Paralysis is triggered by hyperthyroidism.
Thyrotoxic Periodic Paralysis can be diagnosed with a TSH test.
Thyrotoxic Periodic Paralysis is treatable with antithyroid therapy and propanolol.

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Test your knowledge on channelopathies, their genetic causes, and their impact on conditions like epilepsy. This quiz covers crucial aspects of Ohtahara syndrome, including its symptoms, genetic factors, and available treatments. Enhance your understanding of how ion channel disorders affect neurological function.