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ORPHA:85165

Severe achondroplasia-developmental delay-acanthosis nigricans syndrome

high confidenceDisorder

Also known as: SADDAN

Publications

148

51.9th percentile

Trials

0

Interventional, condition-specific

Researchers

881

Distinct authors in sample

Gene link

FGFR3

Strong

Readiness

3/6

Stages with a signal

Clinical definition (Orphanet)

Severe achondroplasia--acanthosis nigricans syndrome is characterised by the association of severe achondroplasia with and acanthosis nigricans. It has been described in four unrelated individuals. Structural central nervous system anomalies, and hearing loss were also reported, together with bowing of the clavicle, femur, tibia and fibula in some cases. The syndrome is caused by a Lys650Met substitution in the kinase domain of fibroblast growth factor receptor 3 (encoded by the FGFR3 gene; 4p16.3).

How rare: <1 / 1 000 000 — fewer than one in a million. In a city the size of Kolkata, that might mean on the order of fifteen people.

Orphanet entry

Cross-references

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

Additional Mondo synonyms (1)

SADDAN dysplasia

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.”

3/6 stages with a signal

No matched interventional trial; the gene is known and literature exists — preclinical or natural-history work may still be the practical next step.

  1. Gene identifiedPresent

    Strong — FGFR3

  2. LiteraturePresent

    148 matched papers (68 in last 10 years) Source

  3. Phenotype characterisedPresent

    60 HPO annotations (e.g. Tibial bowing; Severe short stature; Palmoplantar cutis laxa) 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 trialNot found

    No matched interventional trial under our ClinicalTrials.gov rules

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 (FGFR3).

GenCC classification: Strong.

Phenotypes (Monarch / HPO)

60

Associated phenotypes · MONDO:0014658

  • Tibial bowing
  • Severe short stature
  • Palmoplantar cutis laxa
  • Hearing impairment
  • Femoral bowing

Showing 5 of 60 — 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

No drugs or clinical candidates returned for this Mondo ID on Open Targets.

CTD chemicals (MyDisease.info)

No CTD chemical associations returned for this Mondo ID.

Literature

Is anyone studying this?

148

148 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=3967) is 59.

148 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).

68 in the last 10 years · high confidence · 51.9th percentile (publications denominator)

Phrase hits: 148 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

881

Distinct author names in 148 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.

  1. 01
    Morales-Saldaña S8 papers · 2026

    Instituto de Investigaciones en Ecosistemas y Sustentabilidad, Universidad Nacional Autónoma de México, 58190, Morelia, México.

    Papers in Europe PMC
  2. 02
    Krejci P7 papers · 2022

    Medical Genetics Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA. pavel.krejci@cshs.org

    Papers in Europe PMC
  3. 03
    Donoghue DJ6 papers · 2014
    Papers in Europe PMC
  4. 04
    Ornelas JF6 papers · 2026

    Red de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Xalapa, Veracruz, Mexico.

    Papers in Europe PMC
  5. 05
    Wilcox WR6 papers · 2014

    Department of Human Genetics, Emory University Atlanta, Georgia, 30322 ; Medical Genetics Institute, Cedars-Sinai Medical Center Los Angeles, California ; Department of Pediatrics, UCLA School of Medicine Los Angeles, California.

    Papers in Europe PMC
  6. 06
    Chen L5 papers · 2025

    Center of Bone Metabolism and Repair, Department of Rehabilitation Medicine, State Key Laboratory of Trauma, Burns and Combined Injury, Trauma Center, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, China.

    Papers in Europe PMC
  7. 07
    Francomano CA5 papers · 2001
    Papers in Europe PMC
  8. 08
    Krakow D5 papers · 2026

    Departments of Obstetrics and Gynecology, Orthopaedic Surgery and Human Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California, USA.

    Papers in Europe PMC
  9. 09
    Vásquez-Aguilar AA5 papers · 2026

    Red de Biología Evolutiva, Instituto de Ecología, A.C. (INECOL), Xalapa, Veracruz, Mexico.

    Papers in Europe PMC
  10. 10
    Bellus GA4 papers · 2000

    Department of Dermatology, University of Colorado School of Medicine, Denver, CO 80262, USA. gary.bellus@uchsc.edu

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

0

interventional 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 11 September 2026 · last trial check 11 September 2026

No matched interventional trials. This is true for 77.2% of diseases in the trials denominator (5501 of 7126). Here are the researchers publishing on it.

high confidence · 38.6th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.

See who's working on it — people publishing on this disease are often the practical next contact when no trial is listed.

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 2026-07-30

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 Severe achondroplasia-developmental delay-acanthosis nigricans syndrome — 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.

"Severe achondroplasia-developmental delay-acanthosis nigricans syndrome" OR "SADDAN" OR "SADDAN dysplasia"

Run this search on Europe PMC

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

"Severe achondroplasia-developmental delay-acanthosis nigricans syndrome" OR "SADDAN" OR "SADDAN dysplasia"

Study-type breakdown: 0 interventional · 0 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 2026-07-27T02:46:04.503Z