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ORPHA:461

Recessive X-linked ichthyosis

medium confidenceDisorder

Also known as: RXLI · Steroid sulfatase deficiency · X-linked ichthyosis · XLI

Publications

1,504

84.6th percentile

Trials

0

Interventional, condition-specific

Researchers

999

Distinct authors in sample

Gene link

STS

Definitive

Readiness

5/6

Stages with a signal

Clinical definition (Orphanet)

A rare genetic skin disease belonging to the Mendelian Disorders of Cornification (MeDOC) and characterized by generalized hyperkeratosis and scaling of the skin. The condition is rather mild.

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 (6)

Ichthyosis, X Linked · X-linked recessive ichthyosis · ichthyosis (disease), X-linked · ichthyosis , X-linked, X-linked recessive · recessive X-linked ichthyosis · steroid sulfatase 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.”

5/6 stages with a signal

No specific-condition interventional trial, but broader-category trials exist — discuss eligibility with a clinician.

  1. Gene identifiedPresent

    Definitive — STS

  2. LiteraturePresent

    1,504 matched papers (588 in last 10 years) Source

  3. Phenotype characterisedPresent

    21 HPO annotations (e.g. Palmar hyperlinearity; Congenital ichthyosiform erythroderma; Hypohidrosis) Source

  4. Animal modelNot found

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

  5. Orphan designationPresent

    1 FDA · 2 EMA designations (1 FDA orphan-indication approval) — e.g. urea Source

  6. Interventional trialPartial

    None under the specific name; 30 for broader category ichthyosis

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 (STS).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

21

Associated phenotypes · MONDO:0010622

  • Palmar hyperlinearity
  • Congenital ichthyosiform erythroderma
  • Hypohidrosis
  • Autism

Showing 4 of 21 — 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)

3

Designations · 1 with FDA orphan-indication approval

  • FDA ureaErythroderma Epidermolytic hyperkeratosis Lamellar ichthyosis X-linked ichthyosis Harlequin Ichthyosis Child syndrome Netherton Syndrome Netherton Syndrome Neutral lipid storage disease Trichothiodystrophy Collodion Baby Kid syndrome · 2011-11-07 · Not FDA Approved for Orphan Indication
  • EMA isotretinoinTreatment of recessive X-linked ichthyosis · 15/02/2023 · WithdrawnEMA designation
  • EMA talarozoleTreatment of recessive X-linked ichthyosis · 04/07/2012 · WithdrawnEMA designation

Sources: FDA OOPD · EMA orphan designations

Open Targets candidates

1

Drugs / clinical candidates · MONDO_0010622

CTD chemicals (MyDisease.info)

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

  • Estriol · marker/mechanism

Pathways: Steroid hormone biosynthesis; Metabolism; Gamma carboxylation, hypusine formation and arylsulfatase activation; Glycosphingolipid metabolism; The activation of arylsulfatases; Metabolism of proteins; Sphingolipid metabolism; Metabolism of lipids and lipoproteins

MyDisease.info · MONDO:0010622

Literature

Is anyone studying this?

1,504

1,504 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.

1,504 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).

588 in the last 10 years · medium confidence · 84.6th percentile (publications denominator)

Phrase hits: 1,287 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

999

Distinct author names in 200 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
    Davies W13 papers · 2026

    School of Psychology, Cardiff University, Cardiff, United Kingdom.

    Papers in Europe PMC
  2. 02
    Traupe H9 papers · 2026

    Department of Dermatology, University Hospital of Münster, Münster, Germany.

    Papers in Europe PMC
  3. 03
    Humby T7 papers · 2026

    School of Psychology, Cardiff University, Cardiff, UK.

    Papers in Europe PMC
  4. 04
    Oji V7 papers · 2026

    Department of Dermatology, University of Münster, 48149 Münster, Germany.

    Papers in Europe PMC
  5. 05
    Wren GH7 papers · 2026

    School of Psychology, Cardiff University, Cardiff, United Kingdom.

    Papers in Europe PMC
  6. 06
    Akiyama M6 papers · 2025

    Department of Dermatology, Nagoya University Graduate School of Medicine, Japan. makiyama@med.nagoya-u.ac.jp

    Papers in Europe PMC
  7. 07
    Fischer J6 papers · 2026

    Institute of Human Genetics, Medical Center, Faculty of Medicine, University of Freiburg, DE-79106 Freiburg, Germany. judith.fischer@uniklinik-freiburg.de.

    Papers in Europe PMC
  8. 08
    Paller AS6 papers · 2025

    Department of Dermatology Northwestern University Feinberg School of Medicine Chicago Illinois USA.

    Papers in Europe PMC
  9. 09
    Park H6 papers · 2026

    College of Pharmacy and Center for Metareceptome Research, Chung-Ang University, Seoul, 06974, Republic of Korea.

    Papers in Europe PMC
  10. 10
    Chun YJ5 papers · 2026

    College of Pharmacy and Center for Metareceptome Research, Chung-Ang University, Seoul, 06974, Republic of Korea. yjchun@cau.ac.kr.

    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. 1 observational study did — shown below because natural-history and cohort work can be an important step toward a trial. 30 trials are registered for ichthyosis, the broader category — shown separately because they may or may not enrol this specific subtype.

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.

medium 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.

30 interventional trials matched ichthyosis, the broader category — listed below. Those studies are not counted in the condition-specific total.

Broader category: ichthyosis

30

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.

Recruiting under the broader category

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.

None of the matched observational studies is currently listed as 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 Recessive X-linked ichthyosis — 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.

("Recessive X-linked ichthyosis" OR "Steroid sulfatase deficiency" OR "X-linked ichthyosis" OR "Ichthyosis, X Linked" OR "X-linked recessive ichthyosis" OR "ichthyosis (disease), X-linked" OR "ichthyosis , X-linked, X-linked recessive") OR ("STS syndrome" OR "STS-related")

Run this search on Europe PMC

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

"Recessive X-linked ichthyosis" OR "Steroid sulfatase deficiency" OR "X-linked ichthyosis" OR "Ichthyosis, X Linked" OR "X-linked recessive ichthyosis" OR "ichthyosis (disease), X-linked" OR "ichthyosis , X-linked, X-linked recessive"

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

Parent-category trials query:

"ichthyosis"

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

Run this search on ClinicalTrials.gov

Synonyms dropped by stoplist: RXLI; XLI

Confidence reasoning

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

Ingested 2026-07-26T13:54:19.664Z