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ORPHA:397618

Foveal hypoplasia-optic nerve decussation defect-anterior segment dysgenesis syndrome

medium confidenceDisorder

Also known as: FHONDA syndrome

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

Publications

284

71th percentile

Trials

0

Interventional, condition-specific

Researchers

319

Distinct authors in sample

Gene link

SLC38A8

Definitive

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare, genetic, eye disease characterized by foveal hypoplasia, optic nerve misrouting with an increased number of axons decussating at the optic chiasm and innervating the contralateral cortex, and posterior embryotoxon or Axenfeld anomaly (indicating anterior segment dysgenesis), in the absence of albinism. Patients present nystagmus, decreased visual acuity, refractive errors and, ocassionally, strabismus. Microphthalmia and retinochoroidal coloboma may also be associated.

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 (3)

foveal hypoplasia - optic nerve decussation defect - anterior segment dysgenesis syndrome · foveal hypoplasia 2, with or without optic nerve misrouting and/or anterior segment dysgenesis · foveal hypoplasia type 2

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.”

4/6 stages with a signal

No matched interventional trial, but a gene association and an animal model are on record — often described as translation-ready / stalled at the clinical step.

  1. Gene identifiedPresent

    Definitive — SLC38A8

  2. LiteraturePresent

    284 matched papers (237 in last 10 years) Source

  3. Phenotype characterisedPresent

    11 HPO annotations (e.g. Reduced visual acuity; Hypoplasia of the fovea; Axenfeld anomaly) Source

  4. Animal modelPresent

    1 genotype model (Mus musculus) Source

  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 (SLC38A8).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

11

Associated phenotypes · MONDO:0012216

  • Reduced visual acuity
  • Hypoplasia of the fovea
  • Axenfeld anomaly
  • Alternating esotropia
  • Optic nerve misrouting

Showing 5 of 11 — open Monarch for the full list.

Animal models (Monarch / Alliance)

1

Model associations linked to this Mondo ID

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?

284

284 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.

284 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).

237 in the last 10 years · medium confidence · 71th percentile (publications denominator)

Phrase hits: 42 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

319

Distinct author names in 42 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
    Al-Araimi M4 papers · 2014

    National Genetic Centre, Royal Hospital, Muscat, Oman;

    Papers in Europe PMC
  2. 02
    Ali M4 papers · 2014

    Leeds Institute of Molecular Medicine, Leeds, UK;

    Papers in Europe PMC
  3. 03
    Houshmand M4 papers · 2014

    National Institute for Genetic Engineering & Biotechnology, Tehran, Iran;

    Papers in Europe PMC
  4. 04
    Toomes C4 papers · 2014

    Leeds Institute of Molecular Medicine, Leeds, UK;

    Papers in Europe PMC
  5. 05
    van Genderen MM4 papers · 2022

    Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands.

    Papers in Europe PMC
  6. 06
    Al-Kharusi M3 papers · 2014

    National Genetic Centre, Royal Hospital, Muscat, Oman.

    Papers in Europe PMC
  7. 07
    Arveiler B3 papers · 2025

    Maladies Rares: Génétique et Métabolisme (MRGM), Inserm U1211, University of Bordeaux, Bordeaux, France.

    Papers in Europe PMC
  8. 08
    Aryani O3 papers · 2014

    Department of Medical Genetics, Special Medical Center, Tehran, Iran;

    Papers in Europe PMC
  9. 09
    Bradbury J3 papers · 2014

    Human Genome Sequencing Center, Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, Texas, USA.

    Papers in Europe PMC
  10. 10
    Carr I3 papers · 2014

    Leeds Institute of Molecular Medicine, Leeds, UK;

    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.

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.

Broader category foveal hypoplasia 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: foveal hypoplasia

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.

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 Foveal hypoplasia-optic nerve decussation defect-anterior segment dysgenesis 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.

("Foveal hypoplasia-optic nerve decussation defect-anterior segment dysgenesis syndrome" OR "FHONDA syndrome" OR "foveal hypoplasia - optic nerve decussation defect - anterior segment dysgenesis syndrome" OR "foveal hypoplasia 2, with or without optic nerve misrouting and/or anterior segment dysgenesis" OR "foveal hypoplasia type 2") OR (MESH:"Foveal Hypoplasia and Anterior Segment Dysgenesis") OR ("SLC38A8" OR "SLC38A8 syndrome" OR "SLC38A8-related")

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Foveal Hypoplasia and Anterior Segment Dysgenesis

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

"Foveal hypoplasia-optic nerve decussation defect-anterior segment dysgenesis syndrome" OR "FHONDA syndrome" OR "foveal hypoplasia - optic nerve decussation defect - anterior segment dysgenesis syndrome" OR "foveal hypoplasia 2, with or without optic nerve misrouting and/or anterior segment dysgenesis" OR "foveal hypoplasia type 2" OR "Foveal Hypoplasia and Anterior Segment Dysgenesis"

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

Parent-category trials query:

"foveal hypoplasia"

Query health: suspect — strategies attempted: phrase, mesh; 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
  • Publication count (284) is high for prevalence class "<1 / 1 000 000" — confidence capped at medium

Ingested 2026-07-27T15:11:50.480Z