ORPHA:457284
Houge-Janssens syndrome type 2
Also known as: HJS2 · PPP2R1A-related neurodevelopmental disorder · PPP2R1A-related Houge-Janssens syndrome
Publications
17
32.9th percentile
Trials
0
Interventional, condition-specific
Researchers
116
Distinct authors in sample
Gene link
PPP2R1A
Definitive
Readiness
2/6
Stages with a signal
Clinical definition (Orphanet)
A rare genetic multiple anomalies/ syndrome characterized by variable degrees of and with poor or absent speech, , hypoplastic or absent corpus callosum, and facial dysmorphism (such as long face, frontal bossing, hypertelorism, downslanting palpebral fissures, and tented upper lip). Additional reported features include microcephaly, , gait , scoliosis, and syndactyly of fingers, among others.
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:0014605
- OMIM:616362
- UMLS:C4225352
Additional Mondo synonyms (5)
MRD36 · autosomal dominant intellectual disability 36 · intellectual disability, autosomal dominant type 36 · mental retardation, autosomal dominant type 36 · microcephaly-corpus callosum hypoplasia-intellectual disability-facial dysmorphism syndrome
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 — PPP2R1A
- LiteraturePresent
17 matched papers (15 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 (PPP2R1A).
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?
17
17 papers have ever been indexed 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.
17 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).
15 in the last 10 years · medium confidence · 32.9th percentile (publications denominator)
Phrase hits: 17 · MeSH hits: 0
Who's working on it?
116
Distinct author names in 17 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.
- 01Fu F2 papers · 2023
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
Papers in Europe PMC - 02Han J2 papers · 2023
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
Papers in Europe PMC - 03Lei T2 papers · 2023
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
Papers in Europe PMC - 04Li D2 papers · 2023
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China. drlidongzhi2014@sina.com.
Papers in Europe PMC - 05Li F2 papers · 2022
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
Papers in Europe PMC - 06Li L2 papers · 2023
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
Papers in Europe PMC - 07Liao C2 papers · 2023
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China. canliao6008@163.com.
Papers in Europe PMC - 08Pan M2 papers · 2023
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
Papers in Europe PMC - 09Yang X2 papers · 2023
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
Papers in Europe PMC - 10Zhang Y2 papers · 2022
Department of Prenatal Diagnostic Center, Guangzhou Women and Children's Medical Center, Guangzhou Medical University, Guangzhou, 510623, Guangdong, China.
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.
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.
medium 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.
Broader category Houge-Janssens syndrome also has no matched interventional trial. See who's working on it — people publishing on this disease are often the practical next contact when no trial is listed.
Broader category: Houge-Janssens syndrome
0
Interventional trials for the parent category, exclusive of NCT IDs already counted above. Eligibility for this subtype is not guaranteed.
Parent-category matching found a broader label but no interventional trials under it. How we count trials.
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.
Recruiting or not-yet-recruiting
- NCT01238250·RECRUITING·Online Study of People Who Have Genetic Changes and Features of Autism: Simons Searchlight
Conditions: 16P11.2 Deletion Syndrome · 16p11.2 Duplications · 1Q21.1 Deletion · 1Q21.1 Microduplication Syndrome (Disorder)·Matched via recall expansion
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.
"Houge-Janssens syndrome type 2" OR "PPP2R1A-related neurodevelopmental disorder" OR "PPP2R1A-related Houge-Janssens syndrome" OR "MRD36" OR "autosomal dominant intellectual disability 36" OR "intellectual disability, autosomal dominant type 36" OR "mental retardation, autosomal dominant type 36" OR "microcephaly-corpus callosum hypoplasia-intellectual disability-facial dysmorphism syndrome"
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Houge-Janssens syndrome type 2" OR "PPP2R1A-related neurodevelopmental disorder" OR "PPP2R1A-related Houge-Janssens syndrome" OR "MRD36" OR "autosomal dominant intellectual disability 36" OR "intellectual disability, autosomal dominant type 36" OR "mental retardation, autosomal dominant type 36" OR "microcephaly-corpus callosum hypoplasia-intellectual disability-facial dysmorphism syndrome" OR "PPP2R1A"
Recall-expansion terms: PPP2R1A
Study-type breakdown: 0 interventional · 1 observational · 0 expanded access. Only interventional studies enter the trial headline.
Parent-category trials query:
"Houge-Janssens syndrome"
Query health: ok — strategies attempted: phrase, recall-expansion; with hits: phrase, recall-expansion
Run this search on ClinicalTrials.gov
Synonyms dropped by stoplist: HJS2
Confidence reasoning
- Preferred label is multi-word and distinctive
- 1 synonym(s) dropped by stoplist (may under-count)
- No label/synonym collisions with other diseases in this corpus
Ingested 2026-07-27T16:50:13.118Z