ORPHA:85287
X-linked intellectual disability, Siderius type
Publications
41
42.4th percentile
Trials
0
Interventional, condition-specific
Researchers
267
Distinct authors in sample
Gene link
PHF8
Definitive
Readiness
2/6
Stages with a signal
Clinical definition (Orphanet)
X-linked , Siderius type is characterised by mild to borderline intellectual deficit associated with cleft lip/palate. Preaxial polydactyly, large hands and cryptorchidism are sometimes present. The syndrome has been described in seven boys from two families. Transmission is X-linked and the syndrome is caused by mutations in the PHF8 gene, localised to the p11.21 region of the X chromosome.
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.
Cross-references
Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.
- MONDO:0010286
- MeSH:C537333
- OMIM:300263
- UMLS:C1846055
Additional Mondo synonyms (7)
MRXSSD · Siderius X-linked intellectual disability syndrome · Siderius X-linked mental retardation syndrome · Siderius-Hamel syndrome · intellectual developmental disorder, X-linked, syndromic, Siderius type, X-linked recessive · intellectual disability syndrome, X-linked, Siderius type · syndromic X-linked intellectual disability Siderius type
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.”
2/6 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.
- Gene identifiedPresent
Definitive — PHF8
- LiteraturePresent
41 matched papers (28 in last 10 years) Source
- Phenotype characterisedNot checked
Not yet enriched from Monarch / HPO
- Animal modelNot checked
Not yet enriched from Monarch / Alliance
- Orphan designationNot checked
FDA/EMA orphan-drug designation not enriched yet
- 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 (PHF8).
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?
41
41 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=5449) is 41.
41 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).
28 in the last 10 years · high confidence · 42.4th percentile (publications denominator)
Phrase hits: 41 · MeSH hits: 1
Who's working on it?
267
Distinct author names in 41 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.
- 01Martínez-Balbás MA3 papers · 2026
Department of Molecular Genomics, Instituto de Biología Molecular de Barcelona (IBMB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona 08028, Spain.
Papers in Europe PMC - 02van Bokhoven H3 papers · 2022
Department of Human Genetics, Donders Institute for Brain, Behaviour and Cognition, Radboudumc, Nijmegen, The Netherlands.
Papers in Europe PMC - 03Asensio-Juan E2 papers · 2017
Department of Molecular Genomics, Instituto de Biología Molecular de Barcelona, Spanish Research Council (CSIC), Barcelona Science Park, Barcelona 08028, Spain.
Papers in Europe PMC - 04de la Cruz X2 papers · 2026
Vall d'Hebron Institute of Research (VHIR), Passeig de la Vall d'Hebron, 119, E-08035 Barcelona, Spain.
Papers in Europe PMC - 05Fortschegger K2 papers · 2011
Center for Genomic Regulation, Barcelona Biomedical Research Park, 08003 Barcelona, Spain.
Papers in Europe PMC - 06Gallego C2 papers · 2017
Department of Cell Biology, Instituto de Biología Molecular de Barcelona (IBMB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona 08028, Spain.
Papers in Europe PMC - 07Iacobucci S2 papers · 2026
Department of Molecular Genomics, Instituto de Biología Molecular de Barcelona (IBMB), Consejo Superior de Investigaciones Científicas (CSIC), Barcelona 08028, Spain.
Papers in Europe PMC - 08Kalscheuer VM2 papers · 2022
Max Planck Institute for Molecular Genetics, Research Group Development and Disease, Ihnestr. 63-73, 14195 Berlin, Germany.
Papers in Europe PMC - 09Kremp M2 papers · 2026
Institut für Biochemie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.
Papers in Europe PMC - 10Lee JH2 papers · 2017
Department of Biological Sciences, Konkuk University, Seoul 05029, Korea. kingmega@konkuk.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 on ClinicalTrials.gov (observational studies and pan-disease registries are listed separately when present).
Data as of 27 July 2026
No matched interventional trials. This is true for 73% of diseases in the trials denominator (5114 of 7003). Here are the researchers publishing on it.
high confidence · 36.5th 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.
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 on the overview but are not added to the query string.
"X-linked intellectual disability, Siderius type" OR "MRXSSD" OR "Siderius X-linked intellectual disability syndrome" OR "Siderius X-linked mental retardation syndrome" OR "Siderius-Hamel syndrome" OR "intellectual developmental disorder, X-linked, syndromic, Siderius type, X-linked recessive" OR "intellectual disability syndrome, X-linked, Siderius type" OR "syndromic X-linked intellectual disability Siderius type"
MeSH descriptor terms unioned into the query: Siderius X-linked mental retardation syndrome
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"X-linked intellectual disability, Siderius type" OR "MRXSSD" OR "Siderius X-linked intellectual disability syndrome" OR "Siderius X-linked mental retardation syndrome" OR "Siderius-Hamel syndrome" OR "intellectual developmental disorder, X-linked, syndromic, Siderius type, X-linked recessive" OR "intellectual disability syndrome, X-linked, Siderius type" OR "syndromic X-linked intellectual disability Siderius type" OR "PHF8"
Recall-expansion terms: PHF8
Study-type breakdown: 0 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.
Query health: ok — strategies attempted: phrase, mesh, recall-expansion; with hits: phrase, mesh
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 2026-07-27T02:52:56.135Z