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ORPHA:139557

X-linked distal spinal muscular atrophy type 3

low confidenceDisorder

Also known as: ATP7A-related distal motor neuropathy · DSMAX · SMAX3 · X-linked dHMN3 · X-linked dSMA3 · X-linked distal hereditary motor neuropathy type 3

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

Publications

5,068

Trials

0

Interventional, condition-specific

Researchers

934

Distinct authors in sample

Gene link

ATP7A

Definitive

Readiness

5/6

Stages with a signal

Clinical definition (Orphanet)

X-linked distal spinal muscular atrophy type 3 is a rare distal motor characterized by slowly atrophy and weakness of distal muscles of hands and feet with normal deep tendon reflexes or absent ankle reflexes and minimal or no sensory loss, sometimes mild proximal weakness in the legs and feet and hand deformities in males.

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 (6)

ATP7A spinal muscular atrophy · X-linked dHMN type 3 · X-linked dSMA type 3 · spinal muscular atrophy caused by mutation in ATP7A · spinal muscular atrophy, distal, X-linked 3, X-linked recessive · spinal muscular atrophy, distal, X-linked type 3

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 — ATP7A

  2. LiteraturePresent

    5,068 matched papers (3,375 in last 10 years) Source

  3. Phenotype characterisedPresent

    9 HPO annotations (e.g. Distal sensory impairment; Distal amyotrophy; Abnormal peripheral nervous system morphology) Source

  4. Animal modelPresent

    2 genotype models (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 trialPartial

    None under the specific name; 166 for broader category spinal muscular atrophy

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 (ATP7A).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

9

Associated phenotypes · MONDO:0010338

  • Distal sensory impairment
  • Distal amyotrophy
  • Abnormal peripheral nervous system morphology
  • Distal muscle weakness
  • Hyporeflexia

Showing 5 of 9 — open Monarch for the full list.

Animal models (Monarch / Alliance)

2

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?

5,068

5,068 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=3967) is 59.

5,068 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).

3,375 in the last 10 years · low confidence

Phrase hits: 168 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

934

Distinct author names in 168 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
    Kaler SG13 papers · 2020

    Unit on Human Copper Metabolism, Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1853, USA. kalers@mail.nih.gov

    Papers in Europe PMC
  2. 02
    Wang Y6 papers · 2025

    Department of Biochemistry, University of Missouri, Columbia, Missouri 65211, USA.

    Papers in Europe PMC
  3. 03
    Yi L6 papers · 2021

    China Water Resources Pearl River Planning, Surveying & Designing Co., Ltd., Zhanyi Road 19#, Guangzhou, 510610, China.

    Papers in Europe PMC
  4. 04
    Donsante A5 papers · 2012

    Unit on Human Copper Metabolism, Molecular Medicine Program, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-1853, USA.

    Papers in Europe PMC
  5. 05
    Faundez V5 papers · 2025

    Departments of Cell Biology, Emory University, Atlanta, United States.

    Papers in Europe PMC
  6. 06
    Petris MJ5 papers · 2021

    Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA.

    Papers in Europe PMC
  7. 07
    Celiński M4 papers · 2022

    Central Institute for Labour Protection-National Research Institute, Department of Chemical, Biological and Aerosol Hazards, 00-701 Warsaw, Poland.

    Papers in Europe PMC
  8. 08
    Kozikowski P4 papers · 2022

    Central Institute for Labour Protection-National Research Institute, Department of Chemical, Biological and Aerosol Hazards, 00-701 Warsaw, Poland.

    Papers in Europe PMC
  9. 09
    Møller LB4 papers · 2023

    Kennedy Centre, Glostrup, Denmark.

    Papers in Europe PMC
  10. 10
    Sałasińska K4 papers · 2022

    Central Institute for Labour Protection-National Research Institute, Department of Chemical, Biological and Aerosol Hazards, 00-701 Warsaw, Poland.

    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). 166 trials are registered for spinal muscular atrophy, 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.

low 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.

166 interventional trials matched spinal muscular atrophy, the broader category — listed below. Those studies are not counted in the condition-specific total.

Broader category: spinal muscular atrophy

166

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

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 X-linked distal spinal muscular atrophy type 3 — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

Likely covered — the policy lists Spinal muscular atrophy as a category (Group 3), and this condition is a form of it. Confirm eligibility with a Centre of Excellence.

Group 3 — high-cost / lifelong therapy with careful selection

Up to ₹50 lakh per patient

Financial support at notified Centres of Excellence is the figure commonly cited in recent MoHFW/PIB statements. Many Group 3 patients also use the MoHFW voluntary-contribution / crowdfunding portal.

Eligibility and patient selection rules change. Verify with a CoE; the crowdfunding portal is a separate mechanism from CoE funding. Verify

Centres of Excellence (15)
  • All India Institute of Medical Sciences (AIIMS) — New Delhi, Delhi
  • Maulana Azad Medical College — New Delhi, Delhi
  • Sanjay Gandhi Post Graduate Institute of Medical Sciences — Lucknow, Uttar Pradesh
  • Post Graduate Institute of Medical Education and Research (PGIMER) — Chandigarh, Chandigarh
  • Centre for DNA Fingerprinting & Diagnostics with Nizam’s Institute of Medical Sciences — Hyderabad, Telangana
  • King Edward Memorial Hospital — Mumbai, Maharashtra
  • Institute of Post-Graduate Medical Education and Research (IPGMER) — Kolkata, West Bengal
  • Centre for Human Genetics with Indira Gandhi Hospital — Bengaluru, Karnataka
  • Institute of Child Health and Hospital for Children (ICH & HC) — Chennai, Tamil Nadu
  • All India Institute of Medical Sciences (AIIMS) — Jodhpur, Rajasthan
  • Sree Avittam Thirunal Hospital (SAT), Government Medical College — Thiruvananthapuram, Kerala
  • All India Institute of Medical Sciences (AIIMS) — Bhopal, Madhya Pradesh
  • Regional Institute of Medical Sciences (RIMS) — Imphal, Manipur
  • All India Institute of Medical Sciences (AIIMS) — Patna, Bihar
  • Assam Medical College & Hospital — Dibrugarh, Assam

Voluntary contributions / crowdfunding (separate from CoE funding): https://rarediseases.mohfw.gov.in/

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 distal spinal muscular atrophy type 3" OR "ATP7A-related distal motor neuropathy" OR "DSMAX" OR "SMAX3" OR "X-linked dHMN3" OR "X-linked dSMA3" OR "X-linked distal hereditary motor neuropathy type 3" OR "ATP7A spinal muscular atrophy" OR "X-linked dHMN type 3" OR "X-linked dSMA type 3" OR "spinal muscular atrophy caused by mutation in ATP7A" OR "spinal muscular atrophy, distal, X-linked 3, X-linked recessive" OR "spinal muscular atrophy, distal, X-linked type 3") OR (MESH:"Spinal Muscular Atrophy, Distal, X-Linked 3") OR ("ATP7A" OR "ATP7A syndrome" OR "ATP7A-related")

Run this search on Europe PMC

MeSH descriptor terms unioned into the query: Spinal Muscular Atrophy, Distal, X-Linked 3

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

"X-linked distal spinal muscular atrophy type 3" OR "ATP7A-related distal motor neuropathy" OR "DSMAX" OR "SMAX3" OR "X-linked dHMN3" OR "X-linked dSMA3" OR "X-linked distal hereditary motor neuropathy type 3" OR "ATP7A spinal muscular atrophy" OR "X-linked dHMN type 3" OR "X-linked dSMA type 3" OR "spinal muscular atrophy caused by mutation in ATP7A" OR "spinal muscular atrophy, distal, X-linked 3, X-linked recessive" OR "spinal muscular atrophy, distal, X-linked type 3" OR "Spinal Muscular Atrophy, Distal, X-Linked 3"

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

Parent-category trials query:

"spinal muscular atrophy"

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 (5068) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-27T07:40:38.923Z