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ORPHA:681

Hypokalemic periodic paralysis

medium confidenceDisorder

Also known as: Westphall disease

Publications

2,097

87.1th percentile

Trials

4

Interventional, condition-specific

Researchers

964

Distinct authors in sample

Gene link

—

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare genetic, muscle channelopathy characterized by recurrent episodic attacks of generalized muscle weakness associated with a decrease in blood potassium levels.

How rare: 1-9 / 100 000 — about one to nine people per hundred thousand.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (5)

HKPP · HOKPP · HypoPP · familial periodic paralysis (& [hypokalaemic]) · hypokalemic periodic paralysis

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

4/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedNot found

    No GenCC disease–gene assertion in this build

  2. LiteraturePresent

    2,097 matched papers (948 in last 10 years) Source

  3. Phenotype characterisedPresent

    35 HPO annotations (e.g. Exercise-induced muscle fatigue; Postprandial hyperglycemia; Late-onset proximal muscle weakness) Source

  4. Animal modelPresent

    3 genotype models (Mus musculus) Source

  5. Orphan designationNot found

    No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source

  6. Interventional trialPresent

    4 matched on ClinicalTrials.gov (1 recruiting in sample)

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Not yet — the cause hasn't been pinned down in GenCC.

No strong gene–disease assertion joined for this Orphanet entity.

Phenotypes (Monarch / HPO)

35

Associated phenotypes · MONDO:0008223

  • Exercise-induced muscle fatigue
  • Postprandial hyperglycemia
  • Late-onset proximal muscle weakness
  • Periodic hypokalemic paresis
  • Episodic hypokalemia

Showing 5 of 35 — open Monarch for the full list.

Animal models (Monarch / Alliance)

3

Model associations linked to this Mondo ID

Monarch fetch 2026-07-29

Therapies

Designations, candidates, and chemicals

FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.

Orphan designation (FDA · EMA)

No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.

Open Targets candidates

2

Drugs / clinical candidates · MONDO_0008223

CTD chemicals (MyDisease.info)

11 associated chemicals · 30 pathways. Therapeutic evidence is listed first when present — not a treatment recommendation.

  • Acetazolamide · therapeutic
  • Amiloride · therapeutic
  • Potassium · therapeutic
  • Spironolactone · therapeutic
  • Triamterene · therapeutic
  • aminopyrine, dexamethasone, phenylbutazone, thiamine, vitamin B12 drug combination · marker/mechanism
  • Amiodarone · marker/mechanism
  • Betamethasone · marker/mechanism
  • Cisplatin · marker/mechanism
  • Cocaine · marker/mechanism
  • Triiodothyronine · marker/mechanism

Pathways: MAPK signaling pathway; Calcium signaling pathway; cGMP-PKG signaling pathway; cAMP signaling pathway; Cardiac muscle contraction; Adrenergic signaling in cardiomyocytes; Vascular smooth muscle contraction; Retrograde endocannabinoid signaling

MyDisease.info · MONDO:0008223

Literature

Is anyone studying this?

2,097

2,097 papers have been published on this condition. That is a real research literature — still far smaller than common diseases (breast cancer: over 700,000 papers). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

2,097 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).

948 in the last 10 years · medium confidence · 87.1th percentile (publications denominator)

Phrase hits: 2,097 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

964

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Holm-Yildiz S8 papers · 2026

    From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark. sonja.desiree.holm-yildiz@regionh.dk.

    Papers in Europe PMC
  2. 02
    Cannon SC7 papers · 2025

    Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.

    Papers in Europe PMC
  3. 03
    Vissing J7 papers · 2025

    From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark.

    Papers in Europe PMC
  4. 04
    Witting N7 papers · 2026

    From the Copenhagen Neuromuscular Center, Department of Neurology (S.H.-Y., N.W., J.D., J.d.S.B., T.S., F.F., A.-S.E., J.V.), and Department of Clinical Genetics (M.D.), Rigshospitalet, University of Copenhagen; and Neurology Practice (T.S.), Herlev, Denmark.

    Papers in Europe PMC
  5. 05
    Dysgaard T6 papers · 2026

    Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark.

    Papers in Europe PMC
  6. 06
    Kannuberg L5 papers · 2026

    Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark.

    Papers in Europe PMC
  7. 07
    Krag T5 papers · 2025

    Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark.

    Papers in Europe PMC
  8. 08
    Pedersen BS5 papers · 2025

    Copenhagen Neuromuscular Center, Department of Neurology 8077, Rigshospitalet, University of Copenhagen, Inge Lehmanns Vej 8, 2100, Copenhagen, Denmark.

    Papers in Europe PMC
  9. 09
    DiFranco M4 papers · 2025

    Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.

    Papers in Europe PMC
  10. 10
    Kubota T4 papers · 2026

    Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Osaka, Japan.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

4

interventional trials for this specific condition

4 interventional trials matched this specific condition name; 1 currently recruiting in our sample. 1 trial are registered for periodic paralysis, the broader category — shown separately because they may or may not enrol this specific subtype.

Data as of 11 September 2026

4 interventional trials — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 88.1th percentile).

medium confidence · 88.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

4 interventional trials matched after quoted-phrase search and title/condition post-filter.

Broader category: periodic paralysis

1

Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.

Worth raising with a clinician. How we count trials.

Observational and natural-history studies

1 observational study matches this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.

Recruiting or not-yet-recruiting

Open the complete matched search on ClinicalTrials.gov

Other registries (secondary)

Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.

raw 0 · after dedupe 0 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 0 · dropped 0 · fetched 2026-07-29

Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri

No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).

Where to find support

Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.

Orphanet entry for Hypokalemic periodic paralysis — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

"Hypokalemic periodic paralysis" OR "Westphall disease" OR "HOKPP" OR "HypoPP" OR "familial periodic paralysis (& [hypokalaemic])"

Run this search on Europe PMC

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Hypokalemic periodic paralysis" OR "Westphall disease" OR "HOKPP" OR "HypoPP" OR "familial periodic paralysis (& [hypokalaemic])"

Interventional trials matched via: phrase (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 4 interventional · 1 observational · 0 expanded access. Only interventional studies enter the trial headline.

Parent-category trials query:

"periodic paralysis"

Query health: ok — strategies attempted: phrase; with hits: phrase

Run this search on ClinicalTrials.gov

Synonyms dropped by stoplist: HKPP

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • 1 synonym(s) dropped by stoplist (may under-count)
  • No label/synonym collisions with other diseases in this corpus

Ingested 2026-07-26T14:55:14.727Z