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ORPHA:22

Succinic semialdehyde dehydrogenase deficiency

high confidenceDisorder

Also known as: 4-hydroxybutyric aciduria · Gamma-hydroxybutyric aciduria · SSADH deficiency

Publications

1,566

87.4th percentile

Trials

1

Interventional, condition-specific

Researchers

1,013

Distinct authors in sample

Gene link

ALDH5A1

Definitive

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare neurometabolic disorder of gamma-aminobutyric acid (GABA) metabolism with a nonspecific clinical presentation (ranging from mild to severe) with the most frequent symptoms being cognitive impairment with prominent deficit in expressive language, , , , and behavioral dysregulation.

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.

Orphanet entry

Cross-references

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

Additional Mondo synonyms (2)

gamma-hydroxybutyric aciduria · succinic semialdehyde dehydrogenase deficiency

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 identifiedPresent

    Definitive — ALDH5A1

  2. LiteraturePresent

    1,566 matched papers (1,006 in last 10 years) Source

  3. Phenotype characterisedPresent

    43 HPO annotations (e.g. Hyperkinetic movements; Hypotonia; Elevated CSF gamma-aminobutyric acid concentration) Source

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationNot found

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

  6. Interventional trialPresent

    1 matched on ClinicalTrials.gov

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?

Yes — we know a specific gene responsible (ALDH5A1).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

43

Associated phenotypes · MONDO:0010083

  • Hyperkinetic movements
  • Hypotonia
  • Elevated CSF gamma-aminobutyric acid concentration
  • Hallucinations
  • Aggressive behavior

Showing 5 of 43 — open Monarch for the full list.

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

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

1

Drugs / clinical candidates · MONDO_0010083

CTD chemicals (MyDisease.info)

2 associated chemicals · 9 pathways. Therapeutic evidence is listed first when present — not a treatment recommendation.

  • Vigabatrin · therapeutic
  • 4-hydroxybutyric acid · marker/mechanism

Pathways: Alanine, aspartate and glutamate metabolism; Butanoate metabolism; Metabolic pathways; GABA (gamma-Aminobutyrate) shunt; Neurotransmitter Release Cycle; Transmission across Chemical Synapses; Neuronal System; GABA synthesis, release, reuptake and degradation

MyDisease.info · MONDO:0010083

Literature

Is anyone studying this?

1,566

1,566 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.

1,566 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).

1,006 in the last 10 years · high confidence · 87.4th percentile (publications denominator)

Phrase hits: 621 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,013

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
    Pearl PL47 papers · 2026

    Department of Neurology, Children's National Medical Center, George Washington University School of Medicine, Washington, DC, USA. ppearl@cnmc.org

    Papers in Europe PMC
  2. 02
    Gibson KM46 papers · 2024

    Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Basic Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99202, USA.

    Papers in Europe PMC
  3. 03
    Roullet JB33 papers · 2025

    Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Biomedical Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99204, USA.

    Papers in Europe PMC
  4. 04
    Rotenberg A17 papers · 2026

    From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA.

    Papers in Europe PMC
  5. 05
    Bertoldi M14 papers · 2026

    Department of Neuroscience, Biomedicine and Movement, Section of Biological Chemistry, University of Verona, Strada Le Grazie, 8, 37134 Verona, Italy.

    Papers in Europe PMC
  6. 06
    Salomons GS14 papers · 2020

    Division of Experimental and Systems Pharmacology, College of Pharmacy, Washington State University, Pharmaceutical and Biomedical Sciences Building Room 347, 412 E. Spokane Falls Blvd, Spokane, WA, 99204, USA.

    Papers in Europe PMC
  7. 07
    Tokatly Latzer I14 papers · 2025

    From the Department of Neurology (P.L.P., I.T.L., H.H.C.L., A.R.), Boston Children's Hospital, Harvard Medical School, Boston, MA.

    Papers in Europe PMC
  8. 08
    Arning E13 papers · 2026

    Baylor Scott & White Research Institute, Institute of Metabolic Disease, Dallas, TX, USA.

    Papers in Europe PMC
  9. 09
    Zhang Y13 papers · 2026

    Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing 100191, China.

    Papers in Europe PMC
  10. 10
    DiBacco ML12 papers · 2025

    From the Department of Neurology (M.L.D., P.L.P.) and Neurodevelopmental Core (E.H.), Boston Children's Hospital, Harvard Medical School, MA; Metabolic Unit, Department of Clinical Chemistry, Vrije Universiteit Amsterdam (A.P., G.S.S.), and Department of Genetic Metabolic Diseases, Emma Children's Hospital, University of Amsterdam (G.S.S.), Amsterdam Neuroscience and Amsterdam Gastroenterology & Metabolism, Amsterdam University Medical Centers, the Netherlands; and College of Pharmacy, Department of Pharmacotherapy (J.-B.R., K.M.G.), Washington State University, Spokane.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

1

interventional trials for this specific condition

1 interventional trial matched this specific condition name; none in our sample are currently recruiting.

Data as of 11 September 2026 · last trial check 28 July 2026

1 interventional trial — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 80.1th percentile).

high confidence · 80.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

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

No currently recruiting studies in the matched set. Open the same search on ClinicalTrials.gov.

Observational and natural-history studies

4 observational studies match 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 Succinic semialdehyde dehydrogenase deficiency — 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.

("Succinic semialdehyde dehydrogenase deficiency" OR "4-hydroxybutyric aciduria" OR "Gamma-hydroxybutyric aciduria" OR "SSADH deficiency") OR ("ALDH5A1" OR "ALDH5A1 syndrome" OR "ALDH5A1-related")

Run this search on Europe PMC

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

"Succinic semialdehyde dehydrogenase deficiency" OR "4-hydroxybutyric aciduria" OR "Gamma-hydroxybutyric aciduria" OR "SSADH deficiency"

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

Query 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

Ingested 2026-07-26T12:07:35.139Z