◆

Subtypes

2

Episodic ataxia type 1 (KCNA1) MONDO:0008047

Autosomal dominant cerebellar channelopathy caused by missense variants in KCNA1 (Kv1.1). Characterised by brief (seconds–minutes) attacks of cerebellar ataxia triggered by startle, sudden movement, or exercise, with continuous interictal myokymia (fine muscle rippling).

Episodic ataxia type 2 (CACNA1A) MONDO:0007163

Autosomal dominant cerebellar channelopathy caused primarily by loss-of-function variants in CACNA1A (Cav2.1 P/Q-type calcium channel). Characterised by longer (hours) attacks of cerebellar ataxia, vertigo, and nausea triggered by stress or exertion, with interictal nystagmus. Attacks are typically responsive to acetazolamide.

⚙

Pathophysiology

5

Kv1.1 Loss-of-Function (EA1)

Heterozygous missense variants in KCNA1 produce loss-of-function or dominant-negative Kv1.1 potassium channel tetramers, reducing delayed rectifier K+ current at sites of high Kv1.1 expression (cerebellar basket cells and juxtaparanodes of myelinated peripheral axons).

potassium ion transmembrane transport link ↓ DECREASED

Downstream

Cerebellar Basket Cell Hyperexcitability (EA1)

Peripheral Motor Nerve Hyperexcitability (EA1)

Show evidence (2 references)

PMID:7842011 SUPPORT Human Clinical

"Mutation analysis of the KCNA1 coding region in these families identified four different missense point mutations present in the heterozygous state, indicating that EA/myokymia can result from mutations in this gene."

Original identification of heterozygous KCNA1 missense mutations as the cause of EA1, establishing the Kv1.1 channelopathy mechanism.

PMID:29891059 SUPPORT Human Clinical

"EA1 is caused by heterozygous mutations in KCNA1, which encodes the α1 subunit of a neuronal voltage-gated potassium channel, Kv1.1."

Confirms EA1 as a Kv1.1 channelopathy caused by heterozygous KCNA1 mutations.

Cerebellar Basket Cell Hyperexcitability (EA1)

Reduced Kv1.1 current in cerebellar basket cells prolongs depolarisation and increases repetitive firing, producing aberrant GABAergic inhibition of Purkinje cells and paroxysmal loss of cerebellar output to deep cerebellar nuclei — the putative central mechanism of EA1 attacks.

cerebellar basket cell link

action potential link ↑ INCREASED

cerebellar cortex link

Peripheral Motor Nerve Hyperexcitability (EA1)

Loss of Kv1.1 at juxtaparanodes of myelinated peripheral motor axons increases nerve excitability and produces spontaneous, continuous motor unit discharges manifesting as interictal myokymia.

motor neuron link

action potential link ↑ INCREASED

peripheral nervous system link

Cav2.1 P/Q Channel Loss-of-Function (EA2)

Heterozygous loss-of-function variants in CACNA1A (truncating, missense, splice-site) reduce Cav2.1 P/Q-type calcium channel function. CACNA1A is allelic with SCA6 (CAG expansion) and familial hemiplegic migraine type 1 (gain-of-function missense).

calcium ion transmembrane transport link ↓ DECREASED

Downstream

Purkinje Cell Pacemaking Imprecision (EA2)

Show evidence (2 references)

PMID:8898206 SUPPORT Human Clinical

"In EA-2, we found two mutations disrupting the reading frame. Thus, FHM and EA-2 can be considered as allelic channelopathies."

Original identification of loss-of-function CACNA1A mutations as the cause of EA2, and demonstration of allelism with familial hemiplegic migraine.

PMID:29891059 SUPPORT Human Clinical

"EA2, the most common and best characterized, is caused by heterozygous mutations in CACNA1A, which encodes the α1A subunit of a neuronal voltage-gated calcium channel, Cav2.1."

Confirms EA2 as a Cav2.1 channelopathy caused by heterozygous CACNA1A mutations.

Purkinje Cell Pacemaking Imprecision (EA2)

Reduced Cav2.1 P/Q-type calcium currents destabilise intrinsic pacemaking of cerebellar Purkinje cells, producing imprecise spontaneous firing and episodic loss of cerebellar inhibitory output. 4-aminopyridine restores Purkinje pacemaking precision by prolonging the action potential and increasing the afterhyperpolarisation.

cerebellar Purkinje cell link

synaptic transmission link

cerebellum link

Show evidence (1 reference)

PMID:20505092 SUPPORT Model Organism

"4-AP restores the severely diminished precision of pacemaking in Purkinje cells of EA2 mutant mice by prolonging the action potential and increasing the action potential afterhyperpolarization."

Mechanistic evidence in EA2 mutant mice that Purkinje cell pacemaking precision is disrupted in EA2 and can be restored pharmacologically.

⬡

Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.

●

Phenotypes

6

Ear 1

Vertigo Vertigo (HP:0002321)

Eye 1

Interictal Nystagmus Nystagmus (HP:0000639)

Nervous System 3

Episodic Ataxia Episodic ataxia (HP:0002131)

Dysarthria Dysarthria (HP:0001260)

Migraine Migraine (HP:0002076)

Show evidence (1 reference)

PMID:36592223 SUPPORT Human Clinical

"The spectrum of paroxysmal manifestations encompasses migraine with hemiplegic aura, episodic ataxia, epilepsy and paroxysmal non-epileptic movement disorders."

Review of CACNA1A-related channelopathies noting migraine as a co-occurring paroxysmal manifestation alongside EA2.

Other 1

Myokymia Myokymia (HP:0002411)

Show evidence (1 reference)

PMID:7842011 SUPPORT Human Clinical

"One type of EA is characterized by brief episodes of ataxia with myokymia (rippling of muscles) evident between attacks."

Describes myokymia as the interictal peripheral nerve phenotype that distinguishes EA1 from other episodic ataxias.

🧬

Genetic Associations

2

KCNA1 Pathogenic Variants (EA1)

Autosomal dominant

Show evidence (1 reference)

PMID:7842011 SUPPORT Human Clinical

"Mutation analysis of the KCNA1 coding region in these families identified four different missense point mutations present in the heterozygous state, indicating that EA/myokymia can result from mutations in this gene."

Foundational evidence linking heterozygous KCNA1 missense variants to EA1.

CACNA1A Pathogenic Variants (EA2)

Autosomal dominant

Show evidence (1 reference)

PMID:8898206 SUPPORT Human Clinical

"In EA-2, we found two mutations disrupting the reading frame. Thus, FHM and EA-2 can be considered as allelic channelopathies."

Foundational evidence linking loss-of-function CACNA1A variants to EA2, with allelism to familial hemiplegic migraine.

💊

Treatments

3

Acetazolamide

Action: Pharmacotherapy NCIT:C15986

Agent: acetazolamide ↗

Carbonic anhydrase inhibitor; first-line prophylactic therapy for EA2, reducing attack frequency and severity. Variable benefit in EA1.

Show evidence (1 reference)

PMID:34484942 SUPPORT Human Clinical

"Compared with placebo, fampridine reduced the number of attacks to 63% (95% CI 54%-74%) and acetazolamide to 52% (95% CI 46%-60%)."

Class II evidence from a randomized placebo-controlled crossover trial demonstrating acetazolamide efficacy in reducing EA2 attacks.

4-Aminopyridine

Action: Pharmacotherapy NCIT:C15986

Agent: 4-aminopyridine ↗

Potassium channel blocker used as prophylactic therapy for EA2; restores Purkinje cell firing precision.

Show evidence (2 references)

PMID:21734179 SUPPORT Human Clinical

"Patients receiving placebo had a median monthly attack frequency of 6.50, whereas patients taking 4AP had a frequency of 1.65 (p = 0.03)."

Class II evidence from a 2011 randomized double-blind placebo-controlled crossover trial demonstrating that 4-aminopyridine significantly reduces attack frequency in EA2 and related familial episodic ataxias.

PMID:34484942 SUPPORT Human Clinical

"Compared with placebo, fampridine reduced the number of attacks to 63% (95% CI 54%-74%) and acetazolamide to 52% (95% CI 46%-60%)."

Class II evidence from a randomized placebo-controlled crossover trial demonstrating fampridine (prolonged-release 4-aminopyridine) efficacy in reducing EA2 attacks.

Carbamazepine

Action: Pharmacotherapy NCIT:C15986

Agent: carbamazepine ↗

Sodium channel blocker anti-seizure medication used off-label as symptomatic therapy for EA1 attacks. Acetazolamide is generally less effective in EA1 than in EA2.

{ }

Source YAML

click to show

name: Episodic Ataxia
creation_date: "2026-04-24T00:00:00Z"
updated_date: "2026-04-24T22:40:00Z"
description: >
  Episodic ataxia (EA) is a group of hereditary cerebellar channelopathies
  characterized by paroxysmal attacks of cerebellar dysfunction (ataxia,
  dysarthria, vertigo, nystagmus) with variable interictal findings. At
  least eight genetic subtypes have been described; this entry focuses on
  EA1 and EA2 as the two prototypical and best-characterised channelopathy
  forms. EA1 is caused by pathogenic variants in KCNA1 (encoding the Kv1.1
  voltage-gated potassium channel), and EA2 is caused by pathogenic variants
  in CACNA1A (encoding the Cav2.1 P/Q-type voltage-gated calcium channel;
  allelic with SCA6 and familial hemiplegic migraine type 1). Attacks in
  both forms are often triggered by physical exertion or emotional stress.
  EA1 attacks are brief (seconds to minutes) and associated with interictal
  myokymia. EA2 attacks are longer (hours) and associated with interictal
  nystagmus; they are typically responsive to acetazolamide and 4-aminopyridine.
category: Mendelian
disease_term:
  preferred_term: hereditary episodic ataxia
  term:
    id: MONDO:0016227
    label: hereditary episodic ataxia
parents:
- Hereditary Ataxia
- Channelopathy
has_subtypes:
- name: EA1
  display_name: Episodic ataxia type 1 (KCNA1)
  subtype_term:
    preferred_term: episodic ataxia type 1
    term:
      id: MONDO:0008047
      label: episodic ataxia type 1
  description: >
    Autosomal dominant cerebellar channelopathy caused by missense variants
    in KCNA1 (Kv1.1). Characterised by brief (seconds–minutes) attacks of
    cerebellar ataxia triggered by startle, sudden movement, or exercise,
    with continuous interictal myokymia (fine muscle rippling).
- name: EA2
  display_name: Episodic ataxia type 2 (CACNA1A)
  subtype_term:
    preferred_term: episodic ataxia type 2
    term:
      id: MONDO:0007163
      label: episodic ataxia type 2
  description: >
    Autosomal dominant cerebellar channelopathy caused primarily by loss-of-function
    variants in CACNA1A (Cav2.1 P/Q-type calcium channel). Characterised by longer
    (hours) attacks of cerebellar ataxia, vertigo, and nausea triggered by stress
    or exertion, with interictal nystagmus. Attacks are typically responsive to
    acetazolamide.
pathophysiology:
- name: Kv1.1 Loss-of-Function (EA1)
  description: >
    Heterozygous missense variants in KCNA1 produce loss-of-function or
    dominant-negative Kv1.1 potassium channel tetramers, reducing delayed
    rectifier K+ current at sites of high Kv1.1 expression (cerebellar
    basket cells and juxtaparanodes of myelinated peripheral axons).
  biological_processes:
  - preferred_term: potassium ion transmembrane transport
    term:
      id: GO:0071805
      label: potassium ion transmembrane transport
    modifier: DECREASED
  downstream:
  - target: Cerebellar Basket Cell Hyperexcitability (EA1)
    causal_link_type: DIRECT
  - target: Peripheral Motor Nerve Hyperexcitability (EA1)
    causal_link_type: DIRECT
  evidence:
  - reference: PMID:7842011
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mutation analysis of the KCNA1 coding region in these families identified four different missense point mutations present in the heterozygous state, indicating that EA/myokymia can result from mutations in this gene."
    explanation: Original identification of heterozygous KCNA1 missense mutations as the cause of EA1, establishing the Kv1.1 channelopathy mechanism.
  - reference: PMID:29891059
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "EA1 is caused by heterozygous mutations in KCNA1, which encodes the α1 subunit of a neuronal voltage-gated potassium channel, Kv1.1."
    explanation: Confirms EA1 as a Kv1.1 channelopathy caused by heterozygous KCNA1 mutations.
- name: Cerebellar Basket Cell Hyperexcitability (EA1)
  description: >
    Reduced Kv1.1 current in cerebellar basket cells prolongs depolarisation
    and increases repetitive firing, producing aberrant GABAergic inhibition
    of Purkinje cells and paroxysmal loss of cerebellar output to deep
    cerebellar nuclei — the putative central mechanism of EA1 attacks.
  cell_types:
  - preferred_term: cerebellar basket cell
    term:
      id: CL:0000118
      label: basket cell
  biological_processes:
  - preferred_term: action potential
    term:
      id: GO:0001508
      label: action potential
    modifier: INCREASED
  locations:
  - preferred_term: cerebellar cortex
    term:
      id: UBERON:0002129
      label: cerebellar cortex
- name: Peripheral Motor Nerve Hyperexcitability (EA1)
  description: >
    Loss of Kv1.1 at juxtaparanodes of myelinated peripheral motor axons
    increases nerve excitability and produces spontaneous, continuous
    motor unit discharges manifesting as interictal myokymia.
  cell_types:
  - preferred_term: motor neuron
    term:
      id: CL:0000100
      label: motor neuron
  biological_processes:
  - preferred_term: action potential
    term:
      id: GO:0001508
      label: action potential
    modifier: INCREASED
  locations:
  - preferred_term: peripheral nervous system
    term:
      id: UBERON:0000010
      label: peripheral nervous system
- name: Cav2.1 P/Q Channel Loss-of-Function (EA2)
  description: >
    Heterozygous loss-of-function variants in CACNA1A (truncating, missense,
    splice-site) reduce Cav2.1 P/Q-type calcium channel function. CACNA1A is
    allelic with SCA6 (CAG expansion) and familial hemiplegic migraine type 1
    (gain-of-function missense).
  biological_processes:
  - preferred_term: calcium ion transmembrane transport
    term:
      id: GO:0070588
      label: calcium ion transmembrane transport
    modifier: DECREASED
  downstream:
  - target: Purkinje Cell Pacemaking Imprecision (EA2)
    causal_link_type: DIRECT
  evidence:
  - reference: PMID:8898206
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In EA-2, we found two mutations disrupting the reading frame. Thus, FHM and EA-2 can be considered as allelic channelopathies."
    explanation: Original identification of loss-of-function CACNA1A mutations as the cause of EA2, and demonstration of allelism with familial hemiplegic migraine.
  - reference: PMID:29891059
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "EA2, the most common and best characterized, is caused by heterozygous mutations in CACNA1A, which encodes the α1A subunit of a neuronal voltage-gated calcium channel, Cav2.1."
    explanation: Confirms EA2 as a Cav2.1 channelopathy caused by heterozygous CACNA1A mutations.
- name: Purkinje Cell Pacemaking Imprecision (EA2)
  description: >
    Reduced Cav2.1 P/Q-type calcium currents destabilise intrinsic pacemaking
    of cerebellar Purkinje cells, producing imprecise spontaneous firing and
    episodic loss of cerebellar inhibitory output. 4-aminopyridine restores
    Purkinje pacemaking precision by prolonging the action potential and
    increasing the afterhyperpolarisation.
  cell_types:
  - preferred_term: cerebellar Purkinje cell
    term:
      id: CL:0000121
      label: Purkinje cell
  biological_processes:
  - preferred_term: synaptic transmission
    term:
      id: GO:0007268
      label: chemical synaptic transmission
  locations:
  - preferred_term: cerebellum
    term:
      id: UBERON:0002037
      label: cerebellum
  evidence:
  - reference: PMID:20505092
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "4-AP restores the severely diminished precision of pacemaking in Purkinje cells of EA2 mutant mice by prolonging the action potential and increasing the action potential afterhyperpolarization."
    explanation: Mechanistic evidence in EA2 mutant mice that Purkinje cell pacemaking precision is disrupted in EA2 and can be restored pharmacologically.
phenotypes:
- category: Neurologic
  name: Episodic Ataxia
  diagnostic: true
  phenotype_term:
    preferred_term: Episodic ataxia
    term:
      id: HP:0002131
      label: Episodic ataxia
- category: Neurologic
  name: Myokymia
  subtype: EA1
  phenotype_term:
    preferred_term: Myokymia
    term:
      id: HP:0002411
      label: Myokymia
  evidence:
  - reference: PMID:7842011
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "One type of EA is characterized by brief episodes of ataxia with myokymia (rippling of muscles) evident between attacks."
    explanation: Describes myokymia as the interictal peripheral nerve phenotype that distinguishes EA1 from other episodic ataxias.
- category: Neurologic
  name: Interictal Nystagmus
  subtype: EA2
  phenotype_term:
    preferred_term: Nystagmus
    term:
      id: HP:0000639
      label: Nystagmus
- category: Neurologic
  name: Dysarthria
  phenotype_term:
    preferred_term: Dysarthria
    term:
      id: HP:0001260
      label: Dysarthria
- category: Neurologic
  name: Vertigo
  subtype: EA2
  phenotype_term:
    preferred_term: Vertigo
    term:
      id: HP:0002321
      label: Vertigo
- category: Neurologic
  name: Migraine
  subtype: EA2
  phenotype_term:
    preferred_term: Migraine
    term:
      id: HP:0002076
      label: Migraine
  evidence:
  - reference: PMID:36592223
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The spectrum of paroxysmal manifestations encompasses migraine with hemiplegic aura, episodic ataxia, epilepsy and paroxysmal non-epileptic movement disorders."
    explanation: Review of CACNA1A-related channelopathies noting migraine as a co-occurring paroxysmal manifestation alongside EA2.
genetic:
- name: KCNA1 Pathogenic Variants (EA1)
  subtype: EA1
  inheritance:
  - name: Autosomal dominant
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  notes: >
    Heterozygous missense variants in KCNA1 (Kv1.1 potassium channel) cause EA1
    via loss-of-function or dominant-negative effects on channel tetramers.
  gene_term:
    preferred_term: KCNA1
    term:
      id: hgnc:6218
      label: KCNA1
  evidence:
  - reference: PMID:7842011
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Mutation analysis of the KCNA1 coding region in these families identified four different missense point mutations present in the heterozygous state, indicating that EA/myokymia can result from mutations in this gene."
    explanation: Foundational evidence linking heterozygous KCNA1 missense variants to EA1.
- name: CACNA1A Pathogenic Variants (EA2)
  subtype: EA2
  inheritance:
  - name: Autosomal dominant
    inheritance_term:
      preferred_term: Autosomal dominant inheritance
      term:
        id: HP:0000006
        label: Autosomal dominant inheritance
  notes: >
    Heterozygous loss-of-function variants (truncating, missense, splice-site)
    in CACNA1A cause EA2. The same gene harbours CAG repeat expansions causing
    SCA6 and gain-of-function missense variants causing familial hemiplegic
    migraine type 1.
  gene_term:
    preferred_term: CACNA1A
    term:
      id: hgnc:1388
      label: CACNA1A
  evidence:
  - reference: PMID:8898206
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In EA-2, we found two mutations disrupting the reading frame. Thus, FHM and EA-2 can be considered as allelic channelopathies."
    explanation: Foundational evidence linking loss-of-function CACNA1A variants to EA2, with allelism to familial hemiplegic migraine.
diagnosis:
- name: Clinical Attack Characterization and Interictal Examination
  description: >-
    Clinical diagnosis begins with characterization of attack history: onset
    age, duration (seconds–minutes in EA1; hours in EA2), frequency, and
    associated symptoms (ataxia, dysarthria, nausea, vertigo). Precipitating
    triggers including physical exertion, emotional stress, or startle should
    be documented. Interictal neurological examination is key for subtyping:
    myokymia (rippling of muscles, most visible perioral or in the hands) is
    characteristic of EA1; nystagmus (gaze-evoked or downbeat) is characteristic
    of EA2. Attacks with normal or near-normal interictal neurological function
    indicate episodic channelopathy and should prompt molecular genetic testing.
  diagnosis_term:
    preferred_term: clinical assessment
    term:
      id: MAXO:0000487
      label: clinical assessment
  evidence:
  - reference: PMID:7842011
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Episodic ataxia (EA) is a rare, familial disorder producing attacks of generalized ataxia, with normal or near-normal neurological function between attacks. One type of EA is characterized by brief episodes of ataxia with myokymia (rippling of muscles) evident between attacks."
    explanation: >-
      Describes the core clinical feature (attacks with near-normal interictal
      function) and interictal myokymia as the distinguishing feature of EA1,
      both central to clinical attack characterization and subtype diagnosis.
  - reference: PMID:29891059
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Primary episodic ataxias (EAs) are a group of dominantly inherited disorders characterized by transient recurrent incoordination and truncal instability, often triggered by physical exertion and emotional stress"
    explanation: >-
      Confirms physical exertion and emotional stress as characteristic
      precipitating triggers used in clinical assessment.
- name: Molecular Genetic Testing
  description: >-
    Episodic ataxia is subtyped by molecular genetic testing: episodic ataxia
    type 1 (KCNA1, Kv1.1 channelopathy) and the more common episodic ataxia
    type 2 (CACNA1A, Cav2.1 channelopathy), which guides prognosis and
    acetazolamide-responsive management.
  diagnosis_term:
    preferred_term: molecular genetic testing
    term:
      id: MAXO:0000533
      label: molecular genetic testing
  evidence:
  - reference: PMID:29891059
    reference_title: "Episodic ataxias."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "EA1 is caused by heterozygous mutations in KCNA1, which encodes the α1 subunit of a neuronal voltage-gated potassium channel, Kv1.1."
    explanation: >-
      Supports KCNA1 (Kv1.1) molecular testing for episodic ataxia type 1.
  - reference: PMID:29891059
    reference_title: "Episodic ataxias."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "EA2, the most common and best characterized, is caused by heterozygous mutations in CACNA1A, which encodes the α1A subunit of a neuronal voltage-gated calcium channel, Cav2.1."
    explanation: >-
      Supports CACNA1A (Cav2.1) molecular testing for episodic ataxia type 2.
treatments:
- name: Acetazolamide
  description: >
    Carbonic anhydrase inhibitor; first-line prophylactic therapy for EA2,
    reducing attack frequency and severity. Variable benefit in EA1.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: acetazolamide
      term:
        id: CHEBI:27690
        label: acetazolamide
  evidence:
  - reference: PMID:34484942
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Compared with placebo, fampridine reduced the number of attacks to 63% (95% CI 54%-74%) and acetazolamide to 52% (95% CI 46%-60%)."
    explanation: Class II evidence from a randomized placebo-controlled crossover trial demonstrating acetazolamide efficacy in reducing EA2 attacks.
- name: 4-Aminopyridine
  description: >
    Potassium channel blocker used as prophylactic therapy for EA2; restores
    Purkinje cell firing precision.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: 4-aminopyridine
      term:
        id: CHEBI:34385
        label: 4-aminopyridine
  evidence:
  - reference: PMID:21734179
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Patients receiving placebo had a median monthly attack frequency of 6.50, whereas patients taking 4AP had a frequency of 1.65 (p = 0.03)."
    explanation: Class II evidence from a 2011 randomized double-blind placebo-controlled crossover trial demonstrating that 4-aminopyridine significantly reduces attack frequency in EA2 and related familial episodic ataxias.
  - reference: PMID:34484942
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Compared with placebo, fampridine reduced the number of attacks to 63% (95% CI 54%-74%) and acetazolamide to 52% (95% CI 46%-60%)."
    explanation: Class II evidence from a randomized placebo-controlled crossover trial demonstrating fampridine (prolonged-release 4-aminopyridine) efficacy in reducing EA2 attacks.
- name: Carbamazepine
  description: >
    Sodium channel blocker anti-seizure medication used off-label as symptomatic
    therapy for EA1 attacks. Acetazolamide is generally less effective in EA1
    than in EA2.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: carbamazepine
      term:
        id: CHEBI:3387
        label: carbamazepine

📚

References & Deep Research

Deep Research

1

Falcon ▸

Disease Characteristics Research Template

Edison Scientific Literature 31 citations 2026-04-24T14:58:31.436379

Question: You are an expert researcher providing comprehensive, well-cited information.

Provide detailed information focusing on: 1. Key concepts and definitions with current understanding 2. Recent developments and latest research (prioritize 2023-2024 sources) 3. Current applications and real-world implementations 4. Expert opinions and analysis from authoritative sources 5. Relevant statistics and data from recent studies

Format as a comprehensive research report with proper citations. Include URLs and publication dates where available. Always prioritize recent, authoritative sources and provide specific citations for all major claims.

Disease Characteristics Research Template

Target Disease

Disease Name: Episodic Ataxia
MONDO ID: (if available)
Category: Mendelian

Research Objectives

Please provide a comprehensive research report on Episodic Ataxia covering all of the disease characteristics listed below. This report will be used to populate a disease knowledge base entry. Be thorough and cite primary literature (PMID preferred) for all claims.

For each section, suggested databases/resources are listed. These are the first places you should search for information on each topic.

1. Disease Information

Search first: OMIM, Orphanet, ICD-10/ICD-11, MeSH, PubMed

What is the disease? Provide a concise overview.
What are the key identifiers? (OMIM, Orphanet, ICD-10/ICD-11, MeSH, Mondo)
What are the common synonyms and alternative names?
Is the information derived from individual patients (e.g., EHR) or aggregated disease-level resources?

2. Etiology

Disease Causal Factors: What are the primary causes? (genetic, environmental, infectious, mechanistic)
Risk Factors:

Search first: PubMed, Cochrane Library, UpToDate, clinical guidelines, ClinVar, ClinGen, GWAS Catalog, PheGenI, CTD, CDC, WHO, epidemiological databases
Genetic risk factors (causal variants, susceptibility loci, modifier genes)
Environmental risk factors (toxins, lifestyle, occupational exposures, age, sex, family history)
Protective Factors:

Search first: PubMed, Cochrane Library, clinical trial databases, GWAS Catalog, gnomAD, WHO, CDC, nutrition databases
Genetic protective factors (protective variants, modifier alleles)
Environmental protective factors (diet, lifestyle, exposures that reduce risk)
Gene-Environment Interactions: How do genetic and environmental factors interact to influence disease?

Search first: CTD, PubMed, PheGenI, GxE databases

3. Phenotypes

Search first: HPO (Human Phenotype Ontology), OMIM, Orphanet, PubMed, clinicaltrials.gov, MedDRA, SNOMED CT, DECIPHER, LOINC

For each phenotype, provide: - Phenotype type: symptoms, clinical signs, physical manifestations, behavioral changes, or laboratory abnormalities

For symptoms/signs: HPO, OMIM, Orphanet, PubMed For behavioral changes: HPO, DSM, RDoC (Research Domain Criteria), PubMed For laboratory abnormalities: LOINC, SNOMED CT, LabTests Online, PubMed - Phenotype characteristics: Search first: OMIM, Orphanet, HPO, PubMed - Age of symptom onset (neonatal, childhood, adult-onset, late-onset) - Symptom severity (mild, moderate, severe, variable) - Symptom progression (stable, progressive, episodic, fluctuating) - Frequency among affected individuals (percentage or qualitative) - Quality of life impact: Effects on daily functioning and well-being (per-phenotype when possible) Search first: EQ-5D database, SF-36, WHO QOL databases, PubMed - Suggest HPO (Human Phenotype Ontology) terms for each phenotype

4. Genetic/Molecular Information

Causal Genes: Gene mutations or chromosomal abnormalities responsible for disease (gene symbols, OMIM IDs)

Search first: OMIM, ClinVar, HGMD, Ensembl, NCBI Gene
Pathogenic Variants:
Affected genes (gene symbols, HGNC IDs) > Search first: OMIM, NCBI Gene, Ensembl, HGNC, UniProt, GeneCards
Variant classification (pathogenic, likely pathogenic, VUS per ACMG/AMP guidelines) > Search first: ClinVar, ClinGen, ACMG/AMP guidelines, VarSome
Variant type/class (missense, frameshift, nonsense, splice-site, structural)
Allele frequency in population databases > Search first: gnomAD, 1000 Genomes, ExAC, TOPMed, dbSNP
Somatic vs germline origin > Search first: COSMIC (somatic), ClinVar, ICGC, TCGA
Functional consequences (loss of function, gain of function, dominant negative)
Modifier Genes: Genes that modify disease severity or expression
Epigenetic Information: DNA methylation, histone modifications, chromatin changes affecting disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Chromosomal Abnormalities: Large-scale genetic changes (aneuploidy, translocations, inversions)

Search first: DECIPHER, ClinVar, ECARUCA, UCSC Genome Browser

5. Environmental Information

Environmental Factors: Non-genetic contributing factors (toxins, radiation, pollution, occupational exposure)

Search first: CTD (Comparative Toxicogenomics Database), TOXNET, PubMed, EPA databases
Lifestyle Factors: Behavioral factors (smoking, diet, exercise, alcohol consumption)

Search first: CDC databases, WHO, PubMed, NHANES
Infectious Agents: If applicable, pathogens causing or triggering disease (bacteria, viruses, fungi, parasites)

Search first: NCBI Taxonomy, ViPR, BV-BRC, MicrobeDB, GIDEON

6. Mechanism / Pathophysiology

Molecular Pathways: Specific signaling cascades or biochemical pathways involved (Wnt, MAPK, mTOR, PI3K-AKT, etc.)

Search first: KEGG, Reactome, WikiPathways, PathBank, BioCyc
Cellular Processes: Cell-level mechanisms (apoptosis, autophagy, cell cycle dysregulation, inflammation, etc.)

Search first: Gene Ontology (GO), Reactome, KEGG, PubMed
Protein Dysfunction: How protein structure or function is altered (misfolding, aggregation, loss of function, gain of function)

Search first: UniProt, PDB (Protein Data Bank), InterPro, Pfam, AlphaFold
Metabolic Changes: Alterations in metabolic processes (energy metabolism, lipid metabolism, amino acid metabolism)

Search first: KEGG, BioCyc, HMDB (Human Metabolome Database), BRENDA
Immune System Involvement: Role of immune response (autoimmunity, immunodeficiency, chronic inflammation)

Search first: ImmPort, Immunome Database, IEDB, Gene Ontology
Tissue Damage Mechanisms: How tissues/ are injured (oxidative stress, ischemia, fibrosis, necrosis)

Search first: PubMed, Gene Ontology, Reactome
Biochemical Abnormalities: Specific molecular defects (enzyme deficiencies, receptor dysfunction, ion channel defects)

Search first: BRENDA, UniProt, KEGG, OMIM, PubMed
Epigenetic Changes: DNA methylation, histone modifications affecting gene expression in disease

Search first: ENCODE, Roadmap Epigenomics, MethBase, DiseaseMeth
Molecular Profiling (if available):
Transcriptomics/gene expression changes > Search first: GEO (Gene Expression Omnibus), ArrayExpress, GTEx, Human Cell Atlas, SRA
Proteomics findings > Search first: PRIDE, ProteomeXchange, Human Protein Atlas, STRING, BioGRID
Metabolomics signatures > Search first: MetaboLights, Metabolomics Workbench, HMDB, METLIN
Lipidomics alterations > Search first: LIPID MAPS, SwissLipids, LipidHome, Metabolomics Workbench
Genomic structural features > Search first: UCSC Genome Browser, Ensembl, NCBI, dbVar, DGV
Advanced Technologies (if applicable):
Single-cell analysis findings (cell-type specific mechanisms, cellular heterogeneity) > Search first: Human Cell Atlas, Single Cell Portal, GEO, CELLxGENE
Spatial transcriptomics findings > Search first: GEO, Spatial Research, Vizgen, 10x Genomics data
Multi-omics integration results > Search first: TCGA, ICGC, cBioPortal, LinkedOmics, PubMed
Functional genomics screens (CRISPR, RNAi) > Search first: DepMap, GenomeRNAi, PubMed, BioGRID ORCS

For each mechanism, describe: - The causal chain from initial trigger to clinical manifestation - Which mechanisms are upstream vs downstream - What cell types and biological processes are involved - Suggest GO terms for biological processes and CL terms for cell types

7. Anatomical Structures Affected

Organ Level:
Primary organs directly affected
Secondary organ involvement (complications, secondary effects)
Body systems involved (cardiovascular, nervous, digestive, respiratory, endocrine, etc.)

Search first: Uberon, FMA (Foundational Model of Anatomy), OMIM, HPO, ICD-11, MeSH, SNOMED CT
Tissue and Cell Level:
Specific tissue types affected (epithelial, connective, muscle, nervous)
Specific cell populations targeted (with Cell Ontology terms)

Search first: Uberon, Human Protein Atlas, Cell Ontology, Human Cell Atlas, CellMarker, PanglaoDB
Subcellular Level:
Cellular compartments involved (mitochondria, nucleus, ER, lysosomes) (with GO Cellular Component terms)

Search first: Gene Ontology (Cellular Component), UniProt, Human Protein Atlas
Localization:
Specific anatomical sites (with UBERON terms) > Search first: FMA, Uberon, NeuroNames (for brain), SNOMED CT
Lateralization (unilateral, bilateral, asymmetric) > Search first: HPO, clinical literature, imaging databases

8. Temporal Development

Onset:
Typical age of onset (congenital, pediatric, adult, geriatric)
Onset pattern (acute, subacute, chronic, insidious)

Search first: OMIM, Orphanet, HPO, PubMed
Progression:
Disease stages (early, intermediate, advanced, end-stage) > Search first: Cancer Staging Manual (AJCC), WHO classifications, PubMed
Progression rate (rapid, slow, variable)
Disease course pattern (episodic, relapsing-remitting, progressive, stable)
Disease duration (self-limited, chronic lifelong)

Search first: Disease registries, longitudinal cohort databases, natural history studies, PubMed, Orphanet, OMIM
Patterns:
Remission patterns (spontaneous, treatment-induced) > Search first: Clinical trial databases, disease registries, PubMed
Critical periods (time windows of vulnerability or opportunity for intervention) > Search first: PubMed, developmental biology databases, clinical guidelines

9. Inheritance and Population

Epidemiology:
Prevalence (cases per 100,000 at given time)
Incidence (new cases per 100,000 per year)

Search first: Orphanet, CDC, WHO, GBD (Global Burden of Disease), national registries, SEER, disease registries
For Genetic Etiology:
Inheritance pattern (AD, AR, X-linked, mitochondrial, multifactorial, polygenic) > Search first: OMIM, Orphanet, ClinVar, GTR (Genetic Testing Registry)
Penetrance (complete, incomplete, age-dependent) > Search first: ClinVar, OMIM, PubMed, ClinGen
Expressivity (variable, consistent) > Search first: OMIM, ClinVar, PubMed
Genetic anticipation (increasing severity in successive generations) > Search first: OMIM, PubMed (especially for repeat expansion disorders)
Germline mosaicism > Search first: ClinVar, OMIM, genetic counseling literature, PubMed
Founder effects (population-specific mutations) > Search first: gnomAD, population genetics databases, PubMed
Consanguinity role > Search first: OMIM, population studies, genetic counseling resources
Carrier frequency > Search first: gnomAD, carrier screening databases, GeneReviews, GTR
Population Demographics:
Affected populations (ethnic or demographic groups with higher prevalence) > Search first: gnomAD, 1000 Genomes, PAGE Study, PubMed, population registries
Geographic distribution (endemic areas, regional variation) > Search first: WHO, CDC, GBD, Orphanet, geographic epidemiology databases
Geographic distribution of specific variants
Sex ratio (male:female) > Search first: Disease registries, OMIM, PubMed, epidemiological databases
Age distribution of affected individuals > Search first: CDC, disease registries, SEER, Orphanet

10. Diagnostics

Clinical Tests:
Laboratory tests (blood, urine, tissue chemistry, specific enzyme assays) > Search first: LOINC, LabTests Online, PubMed
Biomarkers (proteins, metabolites, genetic markers, circulating biomarkers) > Search first: FDA Biomarker List, BEST (Biomarkers, EndpointS, and other Tools), PubMed
Imaging studies (X-ray, CT, MRI, PET, ultrasound) > Search first: RadLex, DICOM, Radiopaedia, imaging databases
Functional tests (pulmonary function, cardiac stress tests) > Search first: LOINC, clinical guidelines, PubMed
Electrophysiology (EEG, EMG, ECG, nerve conduction studies) > Search first: LOINC, clinical neurophysiology databases, PubMed
Biopsy findings (histopathology, immunohistochemistry) > Search first: SNOMED CT, College of American Pathologists resources, PubMed
Pathology findings (microscopic examination) > Search first: SNOMED CT, Digital Pathology databases, PubMed
Genetic Testing:

Search first: GTR (Genetic Testing Registry), GeneReviews, ClinGen
Overview of recommended genetic testing approach
Whole genome sequencing (WGS) utility > Search first: GTR, ClinVar, GEL (Genomics England), gnomAD
Whole exome sequencing (WES) utility > Search first: GTR, ClinVar, OMIM, GeneMatcher
Gene panels (which panels, which genes) > Search first: GTR, ClinVar, laboratory-specific databases
Single gene testing > Search first: GTR, ClinVar, OMIM, GeneReviews
Chromosomal microarray (CMA) > Search first: DECIPHER, ClinVar, dbVar, ECARUCA
Karyotyping > Search first: Chromosome Abnormality Database, ClinVar, cytogenetics resources
FISH > Search first: ClinVar, cytogenetics databases, PubMed
Mitochondrial DNA testing > Search first: MITOMAP, MSeqDR, ClinVar, GTR
Repeat expansion testing > Search first: GTR, ClinVar, repeat expansion databases, PubMed
Omics-Based Diagnostics (if applicable):
RNA sequencing / transcriptomics > Search first: GEO, ArrayExpress, GTEx, RNA-seq databases
Proteomics > Search first: PRIDE, ProteomeXchange, FDA Biomarker database
Metabolomics > Search first: MetaboLights, Metabolomics Workbench, HMDB
Epigenomics > Search first: GEO, ENCODE, Roadmap Epigenomics, MethBase
Liquid biopsy > Search first: COSMIC, ClinVar, liquid biopsy databases, PubMed
Clinical Criteria:
Standardized diagnostic criteria (DSM, ICD, society guidelines) > Search first: DSM-5, ICD-11, clinical society guidelines, UpToDate
Differential diagnosis (other conditions to rule out, with distinguishing features) > Search first: DynaMed, UpToDate, clinical decision support systems
Screening:
Screening methods for asymptomatic individuals (newborn screening, carrier screening, cascade screening) > Search first: ACMG recommendations, CDC newborn screening, GTR

11. Outcome/Prognosis

Survival and Mortality:
Survival rate (5-year, 10-year, overall) > Search first: SEER, cancer registries, disease-specific registries, PubMed
Life expectancy (with and without treatment if applicable) > Search first: Orphanet, disease registries, actuarial databases, PubMed
Mortality rate > Search first: CDC, WHO, GBD, national mortality databases
Disease-specific mortality (deaths directly attributable to disease) > Search first: Disease registries, CDC Wonder, GBD, PubMed
Morbidity and Function:
Morbidity (disease-related disability and health impacts) > Search first: GBD, WHO, disability databases, PubMed
Disability outcomes (long-term functional impairments) > Search first: ICF (International Classification of Functioning), disability registries
Quality of life measures (EQ-5D, SF-36, PROMIS, disease-specific tools) > Search first: EQ-5D database, SF-36, PROMIS, PubMed
Disease Course:
Complications (secondary problems: infections, organ failure, etc.) > Search first: ICD codes, disease registries, clinical databases, PubMed
Recovery potential (likelihood and extent of recovery, with vs without treatment) > Search first: Natural history studies, rehabilitation databases, PubMed
Prediction:
Prognostic factors (age, disease severity, biomarkers, treatment response) > Search first: Prognostic models databases, clinical calculators, PubMed
Prognostic biomarkers (molecular markers predicting disease course) > Search first: FDA Biomarker database, PubMed, cancer prognostic databases

12. Treatment

Pharmacotherapy:
Pharmacological treatments (drug names, drug classes, mechanisms of action) > Search first: DrugBank, RxNorm, ATC classification, DailyMed, FDA databases
Pharmacogenomics (how genetic variants affect drug metabolism, efficacy, toxicity) > Search first: PharmGKB, CPIC (Clinical Pharmacogenetics), FDA Table of PGx Biomarkers
Advanced Therapeutics:
Gene therapy (viral vectors, CRISPR, gene replacement, gene editing) > Search first: ClinicalTrials.gov, FDA gene therapy database, ASGCT resources
Cell therapy (stem cell transplant, CAR-T, cellular therapeutics) > Search first: ClinicalTrials.gov, FDA cell therapy database, FACT standards
RNA-based therapies (ASOs, siRNA, mRNA therapies) > Search first: ClinicalTrials.gov, FDA approvals, PubMed
Targeted therapies (treatments directed at specific molecular targets) > Search first: My Cancer Genome, OncoKB, ClinicalTrials.gov, FDA approvals
Immunotherapies (checkpoint inhibitors, monoclonal antibodies) > Search first: Cancer Immunotherapy Database, FDA approvals, ClinicalTrials.gov
Surgical and Interventional:
Surgical interventions (types of surgery, timing, outcomes) > Search first: CPT codes, surgical registries, clinical guidelines, PubMed
Supportive and Rehabilitative:
Supportive care (symptom management, pain control, nutrition) > Search first: Clinical guidelines, Cochrane Library, PubMed
Rehabilitation (physical therapy, occupational therapy, speech therapy) > Search first: Rehabilitation medicine databases, clinical guidelines, PubMed
Experimental:
Experimental treatments in clinical trials (with NCT identifiers if available) > Search first: ClinicalTrials.gov, EU Clinical Trials Register, WHO ICTRP
Treatment Outcomes:
Treatment response rates > Search first: Clinical trial databases, FDA reviews, systematic reviews, PubMed
Side effects and adverse events > Search first: FDA Adverse Event Reporting System (FAERS), MedWatch, PubMed
Treatment Strategy:
Treatment algorithms (clinical pathways, decision trees) > Search first: Clinical practice guidelines, NCCN Guidelines, UpToDate
Combination therapies > Search first: ClinicalTrials.gov, treatment guidelines, PubMed
Personalized medicine approaches (genotype-guided treatment) > Search first: My Cancer Genome, CIViC, PharmGKB, precision medicine databases

For each treatment, suggest MAXO (Medical Action Ontology) terms where applicable.

13. Prevention

Prevention Levels:
Primary prevention (preventing disease occurrence: vaccination, risk factor modification) > Search first: CDC, WHO, USPSTF recommendations, Cochrane Library
Secondary prevention (early detection and treatment: screening programs, early intervention) > Search first: USPSTF, CDC screening guidelines, WHO
Tertiary prevention (preventing complications in those with disease) > Search first: Clinical guidelines, disease management protocols, PubMed
Immunization: Vaccine strategies (if applicable)

Search first: CDC vaccine schedules, WHO immunization, FDA vaccine database
Screening and Early Detection:
Screening programs (population-based: newborn screening, cancer screening) > Search first: CDC screening programs, USPSTF, cancer screening databases
Genetic screening (carrier screening, preimplantation genetic diagnosis, prenatal testing) > Search first: ACMG recommendations, ACOG guidelines, GTR
Risk stratification (identifying high-risk individuals for targeted prevention) > Search first: Risk prediction models, clinical calculators, PubMed
Behavioral Interventions: Lifestyle modifications to reduce risk

Search first: CDC, WHO, behavioral intervention databases, Cochrane Library
Counseling: Genetic counseling (risk assessment, family planning guidance)

Search first: NSGC resources, ACMG guidelines, GeneReviews
Public Health:
Public health interventions (sanitation, vector control, health education) > Search first: CDC, WHO, public health databases, PubMed
Environmental interventions (reducing environmental risk factors) > Search first: EPA databases, WHO environmental health, PubMed
Prophylaxis: Preventive medications or procedures

Search first: Clinical guidelines, FDA approvals, PubMed

14. Other Species / Natural Disease

Taxonomy: Species affected (with NCBI Taxon identifiers)

Search first: NCBI Taxonomy
Breed: Specific breeds affected (with VBO identifiers if applicable)

Search first: VBO (Vertebrate Breed Ontology)
Gene: Orthologous genes in other species (with NCBI Gene IDs)

Search first: NCBI Gene
Natural Disease:
Naturally occurring disease in other species (companion animals, wildlife) > Search first: OMIA (Online Mendelian Inheritance in Animals), VetCompass, PubMed
Veterinary relevance and importance in animal health > Search first: OMIA, veterinary databases, PubMed
Comparative Biology:
Comparative pathology (similarities and differences across species) > Search first: OMIA, comparative pathology databases, PubMed
Evolutionary conservation of disease mechanisms > Search first: HomoloGene, OrthoMCL, Alliance of Genome Resources
Transmission (if applicable):
Zoonotic potential > Search first: CDC zoonotic diseases, WHO zoonoses, GIDEON
Cross-species susceptibility > Search first: NCBI Taxonomy, veterinary databases, PubMed

15. Model Organisms

Model Types:
Model organism type (mammalian, invertebrate, cellular, in vitro) > Search first: Alliance of Genome Resources, model organism databases
Specific model systems (mouse, rat, zebrafish, Drosophila, C. elegans, yeast, cell lines, organoids, iPSCs) > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, SGD, ATCC, Cellosaurus
Induced models (drug treatment, surgical intervention, environmental manipulation) > Search first: MGI, model organism databases, PubMed
Genetic Models:
Types available (knockout, knock-in, transgenic, conditional, humanized) > Search first: MGI, IMPC, KOMP, EuMMCR, IMSR
Model Characteristics:
Phenotype recapitulation (how well model reproduces human disease features) > Search first: Model organism databases, comparative studies, PubMed
Model limitations (aspects of human disease not captured) > Search first: Model organism databases, PubMed, review articles
Applications:
Research applications (what aspects of disease can be studied) > Search first: Model organism databases, PubMed
Resources:
Model databases > Search first: MGI, RGD, ZFIN, FlyBase, WormBase, IMSR, EMMA, MMRRC

Citation Requirements

Cite primary literature (PMID preferred) for all mechanistic and clinical claims
Prioritize recent reviews and landmark papers
Include direct quotes from abstracts where possible to support key statements
Distinguish evidence source types: human clinical, model organism, in vitro, computational

Output Format

Structure your response as a comprehensive narrative organized by the sections above. For each section, provide: - Factual content with specific details (numbers, percentages, gene names, variant nomenclature) - Ontology term suggestions (HPO, GO, CL, UBERON, CHEBI, MAXO, MONDO) where applicable - Evidence citations with PMIDs - Direct quotes from abstracts to support key claims - Clear indication when information is not available or not applicable for this disease

This report will be used to populate a disease knowledge base entry with: - Pathophysiology descriptions with causal chains - Gene/protein annotations (HGNC, GO terms) - Phenotype associations (HP terms) with frequencies - Cell type involvement (CL terms) - Anatomical locations (UBERON terms) - Chemical entities (CHEBI terms) - Treatment annotations (MAXO terms) - Evidence items with PMIDs and exact abstract quotes - Epidemiology, prognosis, diagnostic, and prevention information - Animal model descriptions with phenotype recapitulation details

Episodic Ataxia (EA) — Comprehensive Disease Characteristics Report (Mendelian)

Target Disease

Disease name: Episodic ataxia (EA) / Hereditary episodic ataxia
Category: Mendelian (predominantly autosomal dominant)
MONDO ID: MONDO:0016227 (“hereditary episodic ataxia”) (hassan2023episodicataxiasprimary pages 15-16)

Executive overview

Episodic ataxia (EA) comprises rare, usually autosomal-dominant disorders characterized by recurrent attacks of cerebellar dysfunction (e.g., gait/limb ataxia, dysarthria, vertigo), with variable attack duration and frequency, and often with interictal findings (e.g., myokymia or nystagmus). (hassan2023episodicataxiasprimary pages 1-2, pilotto2024hereditaryataxiasfrom pages 8-10) A recent classification approach emphasizes describing EA by clinical attack features and interictal signs (Axis 1) plus etiology (Axis 2; inherited vs acquired and neuroimaging features). (hassan2023episodicataxiasprimary pages 15-16)

A key point for real-world practice is that many primary (genetic) and secondary EA mimics are treatable, making cause-finding clinically actionable. (hassan2023episodicataxiasprimary pages 12-13, hassan2023episodicataxiasprimary pages 1-2)

1. Disease information

1.1 Definition and current understanding

EA is described as “rare autosomal dominant disorders with recurrent attacks of cerebellar dysfunction”. (hassan2023episodicataxiasprimary pages 1-2)
A 2024 review similarly defines EA as “a rare group of autosomal-dominant inherited disorders” with recurrent cerebellar dysfunction. (pilotto2024hereditaryataxiasfrom pages 8-10)

1.2 Key identifiers (as available in retrieved sources)

Hereditary episodic ataxia: MONDO:0016227 (hassan2023episodicataxiasprimary pages 15-16)
EA1: OMIM #160120 (pilotto2024hereditaryataxiasfrom pages 8-10)
EA2: OMIM #108500 (indelicato2023cacna1arelatedchannelopathiesclinical pages 4-7, pilotto2024hereditaryataxiasfrom pages 8-10)
Other ontology/identifier mappings (Orphanet ID, ICD-10/ICD-11 codes, MeSH): not found in retrieved sources.

1.3 Synonyms / alternative names (from retrieved sources)

“Episodic ataxia” and “paroxysmal ataxia” are used as search/descriptor terms in a 2023 systematic review of the topic. (hassan2023episodicataxiasprimary pages 15-16)
“Familial episodic ataxia with nystagmus” is used in the context of a randomized trial in EA2 and related familial episodic ataxias. (strupp2011arandomizedtrial pages 1-2)

1.4 Evidence sources

The retrieved evidence is predominantly aggregated disease-level resources (systematic/narrative reviews and trial reports), supplemented by human clinical cohort data (e.g., cognition in EA2) and functional electrophysiology studies for gene expansion of the episodic ataxia phenotype (e.g., SCN8A). (kim2024intellectualdisabilityin pages 1-2, lyu2023clinicalandelectrophysiological pages 1-2)

2. Etiology

2.1 Disease causal factors

Primary genetic (Mendelian) causes (core, gene-defined EAs): - EA1 — KCNA1 (Kv1.1 voltage-gated potassium channel). (hassan2023episodicataxiasprimary pages 4-6, pilotto2024hereditaryataxiasfrom pages 8-10) - EA2 — CACNA1A (Cav2.1 P/Q-type voltage-gated calcium channel α1A subunit). (hassan2023episodicataxiasprimary pages 4-6, indelicato2023cacna1arelatedchannelopathiesclinical pages 4-7, pilotto2024hereditaryataxiasfrom pages 8-10) - Additional gene-defined subtypes highlighted in 2023–2024 reviews: CACNB4 (EA5), SLC1A3 (EA6), UBR4 (EA8). (hassan2023episodicataxiasprimary pages 12-13, pilotto2024hereditaryataxiasfrom pages 8-10)

Secondary/acquired and mimic etiologies: Secondary causes (vascular, inflammatory, toxic–metabolic) and phenocopies can be more common than “primary” EA in general neurology settings, and EA may be misdiagnosed as migraine, vestibular disorders, anxiety, or functional symptoms. (hassan2023episodicataxiasprimary pages 1-2)

2.2 Risk factors

Genetic: autosomal dominant inheritance is typical; de novo variants occur (e.g., KCNA1 de novo noted in EA1 context). (hassan2023episodicataxiasprimary pages 2-4)
Attack-triggering factors (often acting as precipitants rather than disease-causing risks): exercise, emotional stress, heat, fever, menstruation, caffeine, alcohol; also reported are sudden movement/kinesigenic triggers and startle. (hassan2023episodicataxiasprimary pages 1-2, hassan2023episodicataxiasprimary pages 2-4)

2.3 Protective factors

No genetic or environmental protective factors were identified in the retrieved sources.

2.4 Gene–environment interactions

While formal GxE studies were not retrieved, multiple reviews emphasize that physiologic and environmental stressors (exercise, fever/heat, caffeine/alcohol) can trigger attacks, implying that the clinical phenotype emerges from interaction between an underlying channelopathy and state-dependent excitability changes. (hassan2023episodicataxiasprimary pages 1-2, hassan2023episodicataxiasprimary pages 2-4, hassan2023episodicataxiasprimary pages 6-7)

3. Phenotypes

3.1 Core phenotype (umbrella EA)

Attacks may range from seconds/minutes to hours/days, and frequency may range from multiple per day to monthly; gait impairment may range from mild to inability to walk during attacks. (hassan2023episodicataxiasprimary pages 2-4)

3.2 EA1 phenotype (KCNA1)

Typical features (human clinical): - Classical feature: constant myokymia affecting “almost all” patients in classic descriptions. (hassan2023episodicataxiasprimary pages 1-2) - Onset: typically childhood; one review reports mean onset ~7.8 years (not restricted to EA1 only, but presented in EA context with childhood predominance). (hassan2023episodicataxiasprimary pages 1-2) - Attack duration: typically seconds to minutes. (pilotto2024hereditaryataxiasfrom pages 8-10) - Triggers: exercise and other physiological stressors. (hassan2023episodicataxiasprimary pages 2-4)

Suggested HPO terms (examples): - Episodic ataxia (HP:0002135), Gait ataxia (HP:0002066), Dysarthria (HP:0001260) - Myokymia (HP:0002353)

3.3 EA2 phenotype (CACNA1A)

Defining features and frequencies (human clinical): - EA2 is described as the most common hereditary EA. (hassan2023episodicataxiasprimary pages 4-6) - Attacks: “intermittent spells of ataxia and dysarthria lasting several hours, possibly up to 2–3 days.” (hassan2023episodicataxiasprimary pages 4-6) - Interictal findings: “interictal nystagmus between attacks” is a distinguishing feature and is used diagnostically. (hassan2023episodicataxiasprimary pages 4-6, hassan2023episodicataxiasprimary pages 6-7) - Triggers: “emotional or physiological stress, exercise, alcohol and caffeine.” (hassan2023episodicataxiasprimary pages 4-6) - Migraine comorbidity: “reported in up to 50% of cases.” (hassan2023episodicataxiasprimary pages 4-6)

Neuropsychiatric/cognitive features (2024 cohort): A 2019–2023 Korean multicenter cohort of 13 genetically confirmed EA2 patients found substantial cognitive impact: 38.5% met criteria for intellectual disability (FSIQ ≤69), 7.7% borderline (70–79), and 38.5% low average (80–89). (kim2024intellectualdisabilityin pages 1-2)

Suggested HPO terms (examples): - Episodic ataxia (HP:0002135), Vertigo (HP:0002321), Nystagmus (HP:0000639) - Downbeat nystagmus (HP:0000630), Gaze-evoked nystagmus (HP:0000612) - Migraine (HP:0002076) - Intellectual disability (HP:0001249)

3.4 Expanded/atypical episodic ataxia phenotypes (gene discovery and pleiotropy)

EA-like presentations are increasingly recognized across a broader genetic landscape (e.g., epilepsy genes and other ataxia genes), complicating diagnosis but enabling precision treatment when identified. (hassan2023episodicataxiasprimary pages 12-13, hassan2023episodicataxiasprimary pages 1-2)
Example: SCN8A variants can cause episodic or chronic ataxia; in a cohort of 10 individuals from 9 families, several variants produced loss-of-function electrophysiological profiles, and sodium channel blockers worsened symptoms in 4 individuals. (lyu2023clinicalandelectrophysiological pages 1-2, lyu2023clinicalandelectrophysiological pages 4-6)

3.5 Quality of life impact

Direct quality-of-life quantification in EA2 is supported by the randomized trial showing improvement in a vestibular/daily-life score (VDADL) with 4-aminopyridine. (strupp2011arandomizedtrial pages 1-2)

4. Genetic / molecular information

4.1 Causal genes (core)

KCNA1 (EA1) and CACNA1A (EA2) are consistently emphasized as the most frequent/encountered genetic causes. (hassan2023episodicataxiasprimary pages 1-2, pilotto2024hereditaryataxiasfrom pages 8-10)
CACNB4 (EA5), SLC1A3 (EA6), UBR4 (EA8) are additional gene-defined EA entities emphasized in 2023–2024 summaries. (hassan2023episodicataxiasprimary pages 12-13, pilotto2024hereditaryataxiasfrom pages 8-10)

4.2 Variant types and functional consequences

EA1 / KCNA1: primarily missense variants with loss-of-function mechanisms; one review notes “63 KCNA1 pathogenic mutations are reported on OMIM” and that “over half of KCNA1 variants result in EA1.” (hassan2023episodicataxiasprimary pages 4-6)
EA2 / CACNA1A: commonly linked to loss-of-function variants; multiple sources emphasize truncating/nonsense/frameshift variants leading to premature stop codons or other frame-interrupting events. (indelicato2023cacna1arelatedchannelopathiesclinical pages 4-7, pilotto2024hereditaryataxiasfrom pages 8-10)
Penetrance: CACNA1A mutations in EA2 are reported as having high but incomplete penetrance (80–90%). (hassan2023episodicataxiasprimary pages 4-6)

4.3 Modifier genes / protective variants

A potential modifier was described in a multi-omics ataxia cohort (modifier of an ATXN2 expansion in ZFYVE26), illustrating how multi-omics can reveal candidate modifiers in complex ataxia presentations; this was not specific to canonical EA1/EA2. (audet2024integrationofmultiomics pages 2-3)

4.4 Epigenetic information / chromosomal abnormalities

Not identified in the retrieved sources.

5. Environmental information

5.1 Environmental and lifestyle factors influencing attacks

Attack triggers commonly include exercise, emotional stress, heat/fever, menstruation, caffeine, and alcohol. (hassan2023episodicataxiasprimary pages 1-2, hassan2023episodicataxiasprimary pages 2-4, hassan2023episodicataxiasprimary pages 6-7)

5.2 Infectious agents

No infectious causal agents were identified; fever is described as a trigger rather than a cause. (hassan2023episodicataxiasprimary pages 1-2)

6. Mechanism / pathophysiology

6.1 EA as cerebellar channelopathy with network consequences

Most identified EA genes encode ion channels (exception noted for UBR4), supporting EA as a channelopathy-driven cerebellar network disorder. (hassan2023episodicataxiasprimary pages 1-2, pilotto2024hereditaryataxiasfrom pages 8-10)

6.2 EA1 (KCNA1) mechanistic concepts

Kv1.1 is abundant in multiple CNS regions including cerebellum, and dysfunction is linked to cerebellar interneuron hyperexcitability with downstream Purkinje cell effects in a review synthesis. (hassan2023episodicataxiasprimary pages 4-6)

6.3 EA2 (CACNA1A) mechanistic concepts and causal chain

Upstream molecular defect: CACNA1A loss-of-function leading to reduced P/Q-type channel function in the cerebellum. (hassan2023episodicataxiasprimary pages 6-7)

Cellular physiology: A key mechanistic model is that P/Q-type Ca2+ channel dysfunction impairs Purkinje cell firing precision/pacemaking, contributing to episodic motor dysfunction. (alvina2010thetherapeuticmode pages 1-2, alvina2010thetherapeuticmode pages 5-6)

Therapeutic mechanism evidence (4-aminopyridine): A mechanistic study in an EA2 mouse model (tg/tg) reports that, contrary to a simplistic “increase firing rate” hypothesis, therapeutic concentrations of 4-aminopyridine do not increase Purkinje firing rate. (alvina2010thetherapeuticmode pages 2-3, alvina2010thetherapeuticmode pages 1-2) Instead, 4-aminopyridine restores precision of Purkinje pacemaking by prolonging action potentials and increasing afterhyperpolarization, with Kv1 family channels (possibly Kv1.5) suggested as likely targets at therapeutic doses. (alvina2010thetherapeuticmode pages 1-2, alvina2010thetherapeuticmode pages 5-6)

6.4 Suggested ontology terms

GO biological process (suggested): - Regulation of membrane potential; synaptic transmission; regulation of neuron firing; motor coordination

CL cell types (suggested): - Cerebellar Purkinje cell (CL term concept), cerebellar molecular layer interneuron (concept), deep cerebellar nuclei neuron (concept)

7. Anatomical structures affected

7.1 Organ/system level

Primary: central nervous system; cerebellar dysfunction is core. (hassan2023episodicataxiasprimary pages 1-2, pilotto2024hereditaryataxiasfrom pages 8-10)

7.2 Tissue/cell level

Cerebellar circuitry implicating Purkinje cells is emphasized, particularly for EA2 pathophysiology and treatment mechanism. (alvina2010thetherapeuticmode pages 1-2, alvina2010thetherapeuticmode pages 5-6)

7.3 Suggested UBERON terms (examples)

Cerebellum (UBERON concept), Cerebellar cortex (UBERON concept), Cerebellar vermis (UBERON concept; atrophy mentioned as an imaging feature in phenotype tables). (szymanowicz2024areviewof pages 5-6)

8. Temporal development

8.1 Onset

EA often begins in childhood; EA1 onset reported around childhood with mean 7.8 years in a review context. (hassan2023episodicataxiasprimary pages 1-2)
EA2 onset is commonly within the first two decades (reported 2–20 years), though late-onset cases exist. (indelicato2023cacna1arelatedchannelopathiesclinical pages 4-7, pilotto2024hereditaryataxiasfrom pages 8-10)

8.2 Course/progression

Although attacks are episodic, reviews note that attacks “may leave permanent cerebellar signs” and that interictal deficits can exist. (hassan2023episodicataxiasprimary pages 12-13)

9. Inheritance and population

9.1 Inheritance

Most core EA entities are autosomal dominant. (hassan2023episodicataxiasprimary pages 1-2, pilotto2024hereditaryataxiasfrom pages 8-10)

9.2 Epidemiology (available estimates)

Incidence/prevalence estimates reported in reviews are consistently <1 per 100,000 (and likely underestimated). (hassan2023episodicataxiasprimary pages 1-2, pilotto2024hereditaryataxiasfrom pages 8-10)

9.3 Population/variant distribution, founder effects

Not identified in the retrieved sources.

10. Diagnostics

10.1 Clinical approach

Diagnostic evaluation integrates clinical characterization (attack duration, triggers, interictal findings such as myokymia/nystagmus), neuroimaging, and EEG (including EEG during provoked attacks in some contexts). (hassan2023episodicataxiasprimary pages 12-13)
EA2 is “usually distinguished from other EAs by attack duration and interictal nystagmus.” (hassan2023episodicataxiasprimary pages 6-7)

10.2 Genetic testing strategy (current practice trends)

For “classical” EA1/EA2 phenotypes: single-gene testing for KCNA1 or CACNA1A is suggested as a straightforward pathway. (hassan2023episodicataxiasprimary pages 12-13, hassan2023episodicataxiasprimary pages 1-2)
For atypical cases: multigene panels/NGS/WES are emphasized. (hassan2023episodicataxiasprimary pages 12-13, hassan2023episodicataxiasprimary pages 1-2)

10.3 Recent developments: multi-omics and long-read sequencing

A 2024 Frontiers in Genetics study applied WGS + RNA-seq + long-read sequencing in a cohort referred for episodic ataxia presentations, highlighting that ataxia-causal variant types can include SNPs, SVs, CNVs, repeat expansions, and splicing defects, and that integrated multi-omics can improve diagnostic yield. (audet2024integrationofmultiomics pages 2-3)

10.4 Differential diagnosis

EA has substantial overlap with migraine and peripheral vestibular disorders, and can be misdiagnosed as anxiety or functional disorders; secondary causes (vascular, inflammatory, toxic-metabolic) should be considered. (hassan2023episodicataxiasprimary pages 1-2)

11. Outcome / prognosis

11.1 Attack outcomes and chronic burden

EA2 and other EAs can show interictal findings and may develop chronic features (e.g., persistent nystagmus/vestibular impairment), but explicit survival or long-term mortality statistics were not available in retrieved sources. (hassan2023episodicataxiasprimary pages 6-7)

11.2 Treatment-responsive outcome metrics

In EA2 and related familial episodic ataxias, 4-aminopyridine improved quality-of-life scores and reduced attack frequency in a randomized crossover trial. (strupp2011arandomizedtrial pages 1-2)

12. Treatment

12.1 Pharmacotherapy (current applications and evidence)

Acetazolamide (carbonic anhydrase inhibitor; commonly first-line for EA2): - Reviews and the RCT background note acetazolamide preventive dosing commonly 250–1000 mg/day. (hassan2023episodicataxiasprimary pages 6-7, strupp2011arandomizedtrial pages 1-2) - Response: “About 50–75% patients report improvement” with acetazolamide in EA2. (hassan2023episodicataxiasprimary pages 6-7) - Adverse effects described include nephrolithiasis/nephrocalcinosis, paresthesia, fatigue, and GI disturbances. (hassan2023episodicataxiasprimary pages 6-7, strupp2011arandomizedtrial pages 1-2)

4-aminopyridine (4-AP; potassium channel blocker) — evidence-based symptomatic prevention in EA2: - A 2011 randomized double-blind placebo-controlled crossover trial (Neurology; DOI in retrieved text) tested 4-AP 5 mg three times daily in 10 subjects (7 genetically confirmed EA2). (strupp2011arandomizedtrial pages 1-2) - Quantitative outcomes: - Median monthly attack frequency: 6.50 (placebo) → 1.65 (4-AP) (p=0.03). (strupp2011arandomizedtrial pages 1-2) - Median monthly attack duration: 13.65 h → 4.45 h (p=0.08). (strupp2011arandomizedtrial pages 1-2) - VDADL score: 6.00 → 1.50 (p=0.02). (strupp2011arandomizedtrial pages 1-2) - Expert interpretation in later review: 4-AP “is also effective, reducing the number of attacks and improving quality of life in an RCT.” (hassan2023episodicataxiasprimary pages 6-7)

Fampridine / dalfampridine (slow-release 4-AP formulations): - A 2023 review highlights slow-release formulations (dalfampridine/fampridine) as effective for EA2 and states: “Fampridine had fewer side effects than acetazolamide.” (hassan2023episodicataxiasprimary pages 6-7)

EA1 symptomatic management (antiseizure medications): - A 2023 review notes that “A variety of antiseizure medications can diminish attacks, including carbamazepine, phenytoin, and lamotrigine,” and that acetazolamide may help in rare cases. (hassan2023episodicataxiasprimary pages 4-6)

12.2 MAXO and CHEBI term suggestions (for knowledge base tagging)

Acetazolamide therapy (MAXO concept); CHEBI: acetazolamide (CHEBI concept)
4-aminopyridine therapy / potassium channel blocker therapy (MAXO concept); CHEBI: 4-aminopyridine (CHEBI concept)

12.3 Experimental/clinical trials

ClinicalTrials.gov entry retrieved: NCT01543750 “4-Aminopyridine in Episodic Ataxia Type 2” (Phase 2), status Withdrawn, enrollment 0. (NCT01543750 chunk 1)

13. Prevention

13.1 Primary prevention

No primary prevention exists for inherited EA1/EA2 beyond reproductive/genetic counseling.

13.2 Secondary/tertiary prevention

Reviews emphasize that EA is “highly treatable” and that early recognition and management are important; the 2024 EA2 cognition cohort concludes that early diagnosis/management may help prevent “irreversible brain dysfunction.” (hassan2023episodicataxiasprimary pages 1-2, kim2024intellectualdisabilityin pages 1-2)

14. Other species / natural disease

No naturally occurring animal disease analogs were identified in the retrieved sources.

15. Model organisms

A mechanistic EA2 mouse model (tg/tg; described as carrying a spontaneous mutation in the pore-forming P/Q-type Ca2+ channel subunit) is used to study Purkinje pacemaking irregularity and pharmacologic rescue by 4-aminopyridine and chlorzoxazone. (alvina2010thetherapeuticmode pages 5-6)

Summary artifact: identifiers and subtype mapping

Disease name	Subtype	OMIM number	MONDO	Causal gene(s)	Brief defining features	Key citations
Hereditary episodic ataxia	Umbrella disorder	not found in retrieved sources	MONDO:0016227	KCNA1, CACNA1A, CACNB4, SLC1A3, UBR4; additional genes proposed/associated in atypical EA presentations	Rare autosomal-dominant group with recurrent attacks of cerebellar dysfunction; estimated prevalence/incidence reported as <1:100,000; EA1 and EA2 are the most common forms (hassan2023episodicataxiasprimary pages 1-2, pilotto2024hereditaryataxiasfrom pages 8-10)	Hassan 2023-03, Tremor and Other Hyperkinetic Movements, https://doi.org/10.5334/tohm.747 (hassan2023episodicataxiasprimary pages 1-2); Pilotto et al. 2024-02, Cells, https://doi.org/10.3390/cells13040319 (pilotto2024hereditaryataxiasfrom pages 8-10)
Episodic ataxia type 1	EA1	OMIM:160120	MONDO:0008047	KCNA1	Childhood-onset episodic ataxia with attacks usually lasting seconds to minutes; interictal myokymia is characteristic and affects almost all patients in classic descriptions; most KCNA1 variants are missense loss-of-function (hassan2023episodicataxiasprimary pages 1-2, hassan2023episodicataxiasprimary pages 4-6, pilotto2024hereditaryataxiasfrom pages 8-10)	Pilotto et al. 2024-02, Cells, https://doi.org/10.3390/cells13040319 (pilotto2024hereditaryataxiasfrom pages 8-10); Hassan 2023-03, Tremor and Other Hyperkinetic Movements, https://doi.org/10.5334/tohm.747 (hassan2023episodicataxiasprimary pages 1-2, hassan2023episodicataxiasprimary pages 4-6)
Episodic ataxia type 2	EA2	OMIM:108500	not found in retrieved sources	CACNA1A	Most common hereditary EA; recurrent vertigo/ataxia and dysarthria lasting hours to 2-3 days, often with interictal nystagmus; migraine reported in up to 50%; typically associated with CACNA1A loss-of-function, often truncating/nonsense/frameshift variants (hassan2023episodicataxiasprimary pages 4-6, hassan2023episodicataxiasprimary pages 6-7, indelicato2023cacna1arelatedchannelopathiesclinical pages 4-7, pilotto2024hereditaryataxiasfrom pages 8-10)	Indelicato & Boesch 2023-01, Handbook of Experimental Pharmacology, https://doi.org/10.1007/164_2022_625 (indelicato2023cacna1arelatedchannelopathiesclinical pages 4-7); Hassan 2023-03, Tremor and Other Hyperkinetic Movements, https://doi.org/10.5334/tohm.747 (hassan2023episodicataxiasprimary pages 4-6, hassan2023episodicataxiasprimary pages 6-7); Pilotto et al. 2024-02, Cells, https://doi.org/10.3390/cells13040319 (pilotto2024hereditaryataxiasfrom pages 8-10)
Episodic ataxia type 3	EA3	not found in retrieved sources	MONDO:0011682	not found in retrieved sources	Reported rare familial episodic ataxia subtype; gene not established in retrieved evidence (hassan2023episodicataxiasprimary pages 6-7)	Hassan 2023-03, Tremor and Other Hyperkinetic Movements, https://doi.org/10.5334/tohm.747 (hassan2023episodicataxiasprimary pages 6-7)
Episodic ataxia type 5	EA5	not found in retrieved sources	MONDO:0013464	CACNB4	Rare EA subtype linked to CACNB4 in retrieved reviews; one of the recognized gene-defined EA forms (hassan2023episodicataxiasprimary pages 12-13, pilotto2024hereditaryataxiasfrom pages 8-10, gasser2010efnsguidelineson pages 4-5)	Pilotto et al. 2024-02, Cells, https://doi.org/10.3390/cells13040319 (pilotto2024hereditaryataxiasfrom pages 8-10); Hassan 2023-03, Tremor and Other Hyperkinetic Movements, https://doi.org/10.5334/tohm.747 (hassan2023episodicataxiasprimary pages 12-13)
Episodic ataxia type 6	EA6	not found in retrieved sources	not found in retrieved sources	SLC1A3	Rare EA subtype associated with SLC1A3/EAAT1; included among recognized gene-defined EA disorders in recent reviews (hassan2023episodicataxiasprimary pages 12-13, gasser2010efnsguidelineson pages 4-5)	Hassan 2023-03, Tremor and Other Hyperkinetic Movements, https://doi.org/10.5334/tohm.747 (hassan2023episodicataxiasprimary pages 12-13); EFNS guideline 2010-02, European Journal of Neurology, https://doi.org/10.1111/j.1468-1331.2009.02873.x (gasser2010efnsguidelineson pages 4-5)
Episodic ataxia type 8	EA8	not found in retrieved sources	not found in retrieved sources	UBR4	Rare proposed/recognized subtype; unlike most known EA genes, UBR4 is not an ion-channel gene in retrieved reviews (hassan2023episodicataxiasprimary pages 1-2, pilotto2024hereditaryataxiasfrom pages 8-10)	Hassan 2023-03, Tremor and Other Hyperkinetic Movements, https://doi.org/10.5334/tohm.747 (hassan2023episodicataxiasprimary pages 1-2); Pilotto et al. 2024-02, Cells, https://doi.org/10.3390/cells13040319 (pilotto2024hereditaryataxiasfrom pages 8-10)

Table: This table summarizes the key nomenclature and identifier information for hereditary episodic ataxia and major subtypes, integrating OMIM and available MONDO IDs with causal genes and concise phenotype definitions. It is useful as a compact reference for disease knowledge base curation and cross-resource mapping.

Notes on evidence gaps vs template requirements

Orphanet IDs, ICD-10/ICD-11 codes, and MeSH identifiers for episodic ataxia/EA1/EA2 were not present in the retrieved literature excerpts; additional database-specific queries would be required to populate those fields.
Several key 2023–2024 sources in the retrieval set provide robust clinical and genetic summaries, but many excerpts do not include PMIDs; therefore, citations here are to retrieved full-text evidence snippets (pqac IDs) with DOIs/URLs and publication months/years when provided in the retrieved metadata.

References

(hassan2023episodicataxiasprimary pages 15-16): Anhar Hassan. Episodic ataxias: primary and secondary etiologies, treatment, and classification approaches. Tremor and Other Hyperkinetic Movements, Mar 2023. URL: https://doi.org/10.5334/tohm.747, doi:10.5334/tohm.747. This article has 31 citations and is from a peer-reviewed journal.
(hassan2023episodicataxiasprimary pages 1-2): Anhar Hassan. Episodic ataxias: primary and secondary etiologies, treatment, and classification approaches. Tremor and Other Hyperkinetic Movements, Mar 2023. URL: https://doi.org/10.5334/tohm.747, doi:10.5334/tohm.747. This article has 31 citations and is from a peer-reviewed journal.
(pilotto2024hereditaryataxiasfrom pages 8-10): Federica Pilotto, Andrea Del Bondio, and Hélène Puccio. Hereditary ataxias: from bench to clinic, where do we stand? Cells, 13:319, Feb 2024. URL: https://doi.org/10.3390/cells13040319, doi:10.3390/cells13040319. This article has 23 citations.
(hassan2023episodicataxiasprimary pages 12-13): Anhar Hassan. Episodic ataxias: primary and secondary etiologies, treatment, and classification approaches. Tremor and Other Hyperkinetic Movements, Mar 2023. URL: https://doi.org/10.5334/tohm.747, doi:10.5334/tohm.747. This article has 31 citations and is from a peer-reviewed journal.
(indelicato2023cacna1arelatedchannelopathiesclinical pages 4-7): Elisabetta Indelicato and Sylvia Boesch. Cacna1a-related channelopathies: clinical manifestations and treatment options. Handbook of experimental pharmacology, pages 227-248, Jan 2023. URL: https://doi.org/10.1007/164_2022_625, doi:10.1007/164_2022_625. This article has 25 citations and is from a peer-reviewed journal.
(strupp2011arandomizedtrial pages 1-2): M. Strupp, R. Kalla, J. Claassen, C. Adrion, U. Mansmann, T. Klopstock, T. Freilinger, H. Neugebauer, R. Spiegel, M. Dichgans, F. Lehmann-Horn, K. Jurkat-Rott, T. Brandt, J.C. Jen, and K. Jahn. A randomized trial of 4-aminopyridine in ea2 and related familial episodic ataxias. Neurology, 77:269-275, Jul 2011. URL: https://doi.org/10.1212/wnl.0b013e318225ab07, doi:10.1212/wnl.0b013e318225ab07. This article has 228 citations and is from a highest quality peer-reviewed journal.
(kim2024intellectualdisabilityin pages 1-2): Seoyeon Kim, Ji-Soo Kim, Seung-Han Lee, Jae-Myung Kim, Seunghee Na, Jae-Hwan Choi, and Hyo-Jung Kim. Intellectual disability in episodic ataxia type 2: beyond paroxysmal vertigo and ataxia. Journal of Clinical Neurology (Seoul, Korea), 20:563-570, Oct 2024. URL: https://doi.org/10.3988/jcn.2024.0274, doi:10.3988/jcn.2024.0274. This article has 2 citations.
(lyu2023clinicalandelectrophysiological pages 1-2): Hang Lyu, Christian M. Boßelmann, Katrine M. Johannesen, Mahmoud Koko, Juan Dario Ortigoza-Escobar, Sergio Aguilera-Albesa, Deyanira Garcia-Navas Núñez, Tarja Linnankivi, Eija Gaily, Henriette J.A. van Ruiten, Ruth Richardson, Cornelia Betzler, Gabriella Horvath, Eva Brilstra, Niels Geerdink, Daniele Orsucci, Alessandra Tessa, Elena Gardella, Zofia Fleszar, Ludger Schöls, Holger Lerche, Rikke S. Møller, and Yuanyuan Liu. Clinical and electrophysiological features of scn8a variants causing episodic or chronic ataxia. eBioMedicine, 98:104855, Dec 2023. URL: https://doi.org/10.1016/j.ebiom.2023.104855, doi:10.1016/j.ebiom.2023.104855. This article has 16 citations and is from a peer-reviewed journal.
(hassan2023episodicataxiasprimary pages 4-6): Anhar Hassan. Episodic ataxias: primary and secondary etiologies, treatment, and classification approaches. Tremor and Other Hyperkinetic Movements, Mar 2023. URL: https://doi.org/10.5334/tohm.747, doi:10.5334/tohm.747. This article has 31 citations and is from a peer-reviewed journal.
(hassan2023episodicataxiasprimary pages 2-4): Anhar Hassan. Episodic ataxias: primary and secondary etiologies, treatment, and classification approaches. Tremor and Other Hyperkinetic Movements, Mar 2023. URL: https://doi.org/10.5334/tohm.747, doi:10.5334/tohm.747. This article has 31 citations and is from a peer-reviewed journal.
(hassan2023episodicataxiasprimary pages 6-7): Anhar Hassan. Episodic ataxias: primary and secondary etiologies, treatment, and classification approaches. Tremor and Other Hyperkinetic Movements, Mar 2023. URL: https://doi.org/10.5334/tohm.747, doi:10.5334/tohm.747. This article has 31 citations and is from a peer-reviewed journal.
(lyu2023clinicalandelectrophysiological pages 4-6): Hang Lyu, Christian M. Boßelmann, Katrine M. Johannesen, Mahmoud Koko, Juan Dario Ortigoza-Escobar, Sergio Aguilera-Albesa, Deyanira Garcia-Navas Núñez, Tarja Linnankivi, Eija Gaily, Henriette J.A. van Ruiten, Ruth Richardson, Cornelia Betzler, Gabriella Horvath, Eva Brilstra, Niels Geerdink, Daniele Orsucci, Alessandra Tessa, Elena Gardella, Zofia Fleszar, Ludger Schöls, Holger Lerche, Rikke S. Møller, and Yuanyuan Liu. Clinical and electrophysiological features of scn8a variants causing episodic or chronic ataxia. eBioMedicine, 98:104855, Dec 2023. URL: https://doi.org/10.1016/j.ebiom.2023.104855, doi:10.1016/j.ebiom.2023.104855. This article has 16 citations and is from a peer-reviewed journal.
(audet2024integrationofmultiomics pages 2-3): Sebastien Audet, Valerie Triassi, Myriam Gelinas, Nab Legault-Cadieux, Vincent Ferraro, Antoine Duquette, and Martine Tetreault. Integration of multi-omics technologies for molecular diagnosis in ataxia patients. Frontiers in Genetics, Jan 2024. URL: https://doi.org/10.3389/fgene.2023.1304711, doi:10.3389/fgene.2023.1304711. This article has 4 citations and is from a peer-reviewed journal.
(alvina2010thetherapeuticmode pages 1-2): Karina Alviña and Kamran Khodakhah. The therapeutic mode of action of 4-aminopyridine in cerebellar ataxia. The Journal of Neuroscience, 30:7258-7268, May 2010. URL: https://doi.org/10.1523/jneurosci.3582-09.2010, doi:10.1523/jneurosci.3582-09.2010. This article has 232 citations.
(alvina2010thetherapeuticmode pages 5-6): Karina Alviña and Kamran Khodakhah. The therapeutic mode of action of 4-aminopyridine in cerebellar ataxia. The Journal of Neuroscience, 30:7258-7268, May 2010. URL: https://doi.org/10.1523/jneurosci.3582-09.2010, doi:10.1523/jneurosci.3582-09.2010. This article has 232 citations.
(alvina2010thetherapeuticmode pages 2-3): Karina Alviña and Kamran Khodakhah. The therapeutic mode of action of 4-aminopyridine in cerebellar ataxia. The Journal of Neuroscience, 30:7258-7268, May 2010. URL: https://doi.org/10.1523/jneurosci.3582-09.2010, doi:10.1523/jneurosci.3582-09.2010. This article has 232 citations.
(szymanowicz2024areviewof pages 5-6): Oliwia Szymanowicz, Artur Drużdż, Bartosz Słowikowski, Sandra Pawlak, Ewelina Potocka, Ulyana Goutor, Mateusz Konieczny, Małgorzata Ciastoń, Aleksandra Lewandowska, Paweł P. Jagodziński, Wojciech Kozubski, and Jolanta Dorszewska. A review of the cacna gene family: its role in neurological disorders. Diseases, 12:90, May 2024. URL: https://doi.org/10.3390/diseases12050090, doi:10.3390/diseases12050090. This article has 57 citations.
(gasser2010efnsguidelineson pages 4-5): T. Gasser, J. Finsterer, J. Baets, C. Van Broeckhoven, S. Di Donato, B. Fontaine, P. De Jonghe, A. Lossos, T. Lynch, C. Mariotti, L. Schöls, A. Spinazzola, Z. Szolnoki, S. J. Tabrizi, C.M.E. Tallaksen, M. Zeviani, J‐M. Burgunder, and H. F. Harbo. Efns guidelines on the molecular diagnosis of ataxias and spastic paraplegias. European Journal of Neurology, 17:179-188, Feb 2010. URL: https://doi.org/10.1111/j.1468-1331.2009.02873.x, doi:10.1111/j.1468-1331.2009.02873.x. This article has 73 citations and is from a domain leading peer-reviewed journal.

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Subtypes

Pathophysiology

Pathograph

Phenotypes

Genetic Associations

Treatments

Source YAML

References & Deep Research

Deep Research

Disease Characteristics Research Template

Target Disease

Research Objectives

1. Disease Information

2. Etiology

3. Phenotypes

4. Genetic/Molecular Information

5. Environmental Information

6. Mechanism / Pathophysiology

7. Anatomical Structures Affected

8. Temporal Development

9. Inheritance and Population

10. Diagnostics

11. Outcome/Prognosis

12. Treatment

13. Prevention

14. Other Species / Natural Disease

15. Model Organisms

Citation Requirements

Output Format

Episodic Ataxia (EA) — Comprehensive Disease Characteristics Report (Mendelian)

Target Disease

Executive overview

1. Disease information

1.1 Definition and current understanding

1.2 Key identifiers (as available in retrieved sources)

1.3 Synonyms / alternative names (from retrieved sources)

1.4 Evidence sources

2. Etiology

2.1 Disease causal factors

2.2 Risk factors

2.3 Protective factors

2.4 Gene–environment interactions

3. Phenotypes

3.1 Core phenotype (umbrella EA)

3.2 EA1 phenotype (KCNA1)

3.3 EA2 phenotype (CACNA1A)

3.4 Expanded/atypical episodic ataxia phenotypes (gene discovery and pleiotropy)

3.5 Quality of life impact

4. Genetic / molecular information

4.1 Causal genes (core)

4.2 Variant types and functional consequences

4.3 Modifier genes / protective variants

4.4 Epigenetic information / chromosomal abnormalities

5. Environmental information

5.1 Environmental and lifestyle factors influencing attacks

5.2 Infectious agents

6. Mechanism / pathophysiology

6.1 EA as cerebellar channelopathy with network consequences

6.2 EA1 (KCNA1) mechanistic concepts

6.3 EA2 (CACNA1A) mechanistic concepts and causal chain

6.4 Suggested ontology terms

7. Anatomical structures affected

7.1 Organ/system level

7.2 Tissue/cell level

7.3 Suggested UBERON terms (examples)

8. Temporal development

8.1 Onset

8.2 Course/progression

9. Inheritance and population

9.1 Inheritance

9.2 Epidemiology (available estimates)

9.3 Population/variant distribution, founder effects

10. Diagnostics

10.1 Clinical approach

10.2 Genetic testing strategy (current practice trends)

10.3 Recent developments: multi-omics and long-read sequencing

10.4 Differential diagnosis

11. Outcome / prognosis