ORPHA:98808
Autosomal dominant dopa-responsive dystonia
Also known as: Autosomal dominant Segawa syndrome · DYT5a · GTPCH1-deficient DRD · GTPCH1-deficient dopa-responsive dystonia · HPD with marked diurnal fluctuation · Hereditary progressive dystonia with marked diurnal fluctuation
Clinical definition (Orphanet)
A rare neurometabolic disorder characterized by childhood-onset dystonia that shows a dramatic and sustained response to low doses of levodopa (L-dopa) and that may be associated with parkinsonism at an older age.
How rare: 1-9 / 1 000 000 — roughly one to nine people per million. In a city the size of Kolkata, perhaps a few dozen.
Is anyone studying this?
175
175 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=183) is 38.
175 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 38 (publications denominator n=183).
56 in the last 10 years · high confidence · 57.4th percentile (publications denominator)
Is a treatment being tested?
0
trials for this specific condition
No interventional trial testing a treatment matched this specific condition name on ClinicalTrials.gov (observational studies and pan-disease registries are listed separately when present).
Data as of 26 July 2026
0
no matched trials for dopa-responsive dystonia, the broader category this belongs to either
Parent-category matching found a broader label but no interventional trials under it. How we count trials.
No matched interventional trials. This is true for 59.2% of diseases in the trials denominator (151 of 255). Here are the researchers publishing on it.
high confidence · 29.6th percentile (trials denominator)
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.
Who's working on it?
693
Distinct author names in 175 sampled papers — named people below.
Who's working on it?
No interventional trial matched this name; these authors publish on it in the sampled literature — a practical starting point for contact.
- 01
- 02Nomura Y17 papers · 2023
Segawa Neurological Clinic for Children, Tokyo, Japan. nomura_y@kt.rim.or.jp
Papers in Europe PMC - 03Nagatsu T15 papers · 2022
Nagoya University Research Institute of Environmental Medicine, Nagoya, Japan . ; Fujita Health University School of Medicine, Toyoake, Aichi, Japan . ; Visiting Professor and Professor Emeritus.
Papers in Europe PMC - 04Ichinose H14 papers · 2006
Institute for Comprehensive Medical Science, Fujita Health University, Aichi, Japan.
Papers in Europe PMC - 05Ohye T8 papers · 2000Papers in Europe PMC
- 06Hirano M7 papers · 2000
Department of Medical Genetics, Nara Medical University, Japan.
Papers in Europe PMC - 07Ueno S7 papers · 2000
Department of Medical Genetics, Nara Medical University, Shijo-cho 840, Kashihara, 634-8521, Nara, Japan. sueno@nmu-gw.cc.naramed-u.ac.jp
Papers in Europe PMC - 08Furukawa Y6 papers · 2025
Centre for Addiction and Mental Health, Clarke Division, Toronto, Ontario, Canada.
Papers in Europe PMC - 09Carducci C4 papers · 2023
Azienda Ospedaliero Universitaria Policlinico Umberto I, 00161 Rome, Italy.
Papers in Europe PMC - 10Imai T4 papers · 1998Papers in Europe PMC
Recruiting interventional trials
Trials testing a treatment from the matched ClinicalTrials.gov set
No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.
Broader category dopa-responsive dystonia also has no matched interventional trial. See who's working on it above — people publishing on this disease are often the practical next contact when no trial is listed.
Where to find support
We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:
India — NPRD
Last verified 2026-07-26This 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 below but are not added to the query string.
"Autosomal dominant dopa-responsive dystonia" OR "Autosomal dominant Segawa syndrome" OR "DYT5a" OR "GTPCH1-deficient DRD" OR "GTPCH1-deficient dopa-responsive dystonia" OR "HPD with marked diurnal fluctuation" OR "Hereditary progressive dystonia with marked diurnal fluctuation"
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Autosomal dominant dopa-responsive dystonia" OR "Autosomal dominant Segawa syndrome" OR "DYT5a" OR "GTPCH1-deficient DRD" OR "GTPCH1-deficient dopa-responsive dystonia" OR "HPD with marked diurnal fluctuation" OR "Hereditary progressive dystonia with marked diurnal fluctuation"
Study-type breakdown: 0 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.
0Query health: ok — strategies attempted: phrase; with hits: phrase
Run this search on ClinicalTrials.gov
Confidence reasoning
- Preferred label is multi-word and distinctive
- No synonyms dropped by stoplist
- No label/synonym collisions with other diseases in this corpus