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ORPHA:232

Sickle cell anemia

high confidenceDisorder

Also known as: Homozygous hemoglobin S · Homozygous sickle cell anemia SS

Query health: suspect — Only one of 2 strategies returned hits (phrase).

Publications

65,835

99.6th percentile

Trials

781

Interventional, condition-specific

Researchers

1,307

Distinct authors in sample

Gene link

HBB

Definitive

Readiness

3/6

Stages with a signal

Clinical definition (Orphanet)

A severe form of sickle cell disease (SCD) characterized by homozygosity for the sickle hemoglobin (HbS) gene and which acutely manifests with severe anemia, susceptibility to severe bacterial infections, and ischemic vasoocclusive accidents (VOA). It is a red cell disease of genetic origin which manifests with hemolytic disease and loss of red cell deformability leading to other occlusive events.

How rare: 1-5 / 10 000 — about one to five people per ten thousand (still uncommon, but less ultra-rare).

Orphanet entry

Cross-references

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

Additional Mondo synonyms (8)

Haemoglobin S disease without crisis · Hb-S/Hb-C disease · Sickle Cell Disease · sickle cell anemia · sickle cell disease · sickle-cell/Hb-C disease without crisis · sickling disorder due to Haemoglobin S · sickling disorder due to Hemoglobin S

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

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

  1. Gene identifiedPresent

    Definitive — HBB

  2. LiteraturePresent

    65,835 matched papers (36,410 in last 10 years) Source

  3. Phenotype characterisedNot checked

    Not yet enriched from Monarch / HPO

  4. Animal modelNot checked

    Not yet enriched from Monarch / Alliance

  5. Orphan designationNot checked

    FDA/EMA orphan-drug designation not enriched yet

  6. Interventional trialPresent

    781 matched on ClinicalTrials.gov (152 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?

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

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

Not enriched in this build — Monarch phenotype joins were not run for this record.

Animal models (Monarch / Alliance)

Not enriched in this build.

Literature

Is anyone studying this?

65,835

65,835 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=5449) is 41.

65,835 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).

36,410 in the last 10 years · high confidence · 99.6th percentile (publications denominator)

Phrase hits: 65,835 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,307

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
    Arnaud C4 papers · 2026

    Referral Center for Sickle Cell Disease, Department of Pediatrics, Centre Hospitalier Intercommunal, Creteil (CHIC Hospital), Creteil, University Paris XII.

    Papers in Europe PMC
  2. 02
    Bartolucci P4 papers · 2026

    Hôpital Henri Mondor Assistance Publique des Hôpitaux de Paris (AP-HP), Univ Paris Est-Créteil, Créteil, France.

    Papers in Europe PMC
  3. 03
    Connes P4 papers · 2026

    Laboratoire Interuniversitaire de Biologie de la Motricité (LIBM) EA7424, Vascular Biology and Red Blood Cell Team, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France.

    Papers in Europe PMC
  4. 04
    DeBaun MR4 papers · 2026

    Department of Pediatrics, Vanderbilt-Meharry Center of Excellence in Sickle Cell Disease, Vanderbilt University Medical Center, Nashville, TN.

    Papers in Europe PMC
  5. 05
    Kamdem A4 papers · 2026

    Referral Center for Sickle Cell Disease, Department of Pediatrics, Centre Hospitalier Intercommunal, Creteil (CHIC Hospital), Creteil, University Paris XII.

    Papers in Europe PMC
  6. 06
    Namazzi R4 papers · 2026

    Department of Paediatrics and Child Health, Makerere University School of Medicine, Kampala, Uganda.

    Papers in Europe PMC
  7. 07
    Rodeghier M4 papers · 2026

    Rodeghier Consultants, Chicago, IL.

    Papers in Europe PMC
  8. 08
    Ware RE4 papers · 2026

    Department of Pediatrics, Division of Hematology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.

    Papers in Europe PMC
  9. 09
    Belozertseva E3 papers · 2026

    Pediatric Department, Sickle Cell Disease Referral Center, Centre Hospitalier Intercommunal de Créteil, Créteil, France.

    Papers in Europe PMC
  10. 10
    Bongomin F3 papers · 2026

    Department of Medical Microbiology and Immunology, Faculty of Medicine, Gulu University, Gulu, Uganda.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

781

interventional trials for this specific condition

781 interventional trials matched this specific condition name; 152 currently recruiting in our sample.

Data as of 27 July 2026

781 interventional trials — more than 73% of diseases in the trials denominator have none at all (5114 of 7003; this disease is at the 99.8th percentile).

high confidence · 99.8th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

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

Observational and natural-history studies

298 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

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 2026-07-26

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.

"Sickle cell anemia" OR "Homozygous hemoglobin S" OR "Homozygous sickle cell anemia SS" OR "Haemoglobin S disease without crisis" OR "Hb-S/Hb-C disease" OR "Sickle Cell Disease" OR "sickle-cell/Hb-C disease without crisis" OR "sickling disorder due to Haemoglobin S" OR "sickling disorder due to Hemoglobin S"

Run this search on Europe PMC

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

"Sickle cell anemia" OR "Homozygous hemoglobin S" OR "Homozygous sickle cell anemia SS" OR "Haemoglobin S disease without crisis" OR "Hb-S/Hb-C disease" OR "Sickle Cell Disease" OR "sickle-cell/Hb-C disease without crisis" OR "sickling disorder due to Haemoglobin S" OR "sickling disorder due to Hemoglobin S" OR "HBB"

Recall-expansion terms: HBB

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: 781 interventional · 298 observational · 5 expanded access. Only interventional studies enter the trial headline.

Query health: suspect — strategies attempted: phrase, recall-expansion; 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 2026-07-26T13:00:10.687Z