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ORPHA:2785

Osteopetrosis with renal tubular acidosis

low confidenceDisorder

Also known as: Carbonic anhydrase 2 deficiency · Guibaud-Vainsel syndrome · Marble brain disease · Mixed RTA · Mixed renal tubular acidosis · Renal tubular acidosis type 3

Publications

2,003

Trials

0

Interventional, condition-specific

Researchers

938

Distinct authors in sample

Gene link

CA2

Definitive

Readiness

5/6

Stages with a signal

Clinical definition (Orphanet)

Osteopetrosis with renal tubular is a rare disorder characterized by osteopetrosis, renal tubular (RTA), and neurological disorders related to cerebral calcifications.

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 (14)

Autosomal Recessive osteopetrosis, type 3 · CA2 osteopetrosis (disease) · OPTB3 · autosomal recessive osteopetrosis type 3 · carbonic anhydrase 2 deficiency · carbonic anhydrase II deficiency · marble brain disease · mixed RTA · mixed renal tubular acidosis · osteopetrosis (disease) caused by mutation in CA2 · osteopetrosis with renal tubular acidosis · osteopetrosis, autosomal recessive 3, with renal tubular acidosis · osteopetrosis, autosomal recessive type 3 · renal tubular acidosis 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 — CA2

  2. LiteraturePresent

    2,003 matched papers (1,282 in last 10 years) Source

  3. Phenotype characterisedPresent

    77 HPO annotations (e.g. Hepatosplenomegaly; Cranial hyperostosis; Visual loss) 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; 17 for broader category osteopetrosis

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 (CA2).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

77

Associated phenotypes · MONDO:0009818

  • Hepatosplenomegaly
  • Cranial hyperostosis
  • Visual loss
  • Elevated serum acid phosphatase
  • Short stature

Showing 5 of 77 — 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?

2,003

2,003 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.

2,003 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).

1,282 in the last 10 years · low confidence

Phrase hits: 307 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

938

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
    Sly WS16 papers · 2004
    Papers in Europe PMC
  2. 02
    Whyte MP8 papers · 2023

    Division of Bone and Mineral Diseases, Department of Internal Medicine Washington University School of Medicine St. Louis MO USA.

    Papers in Europe PMC
  3. 03
    Tashian RE6 papers · 1994
    Papers in Europe PMC
  4. 04
    Aramaki S4 papers · 1998

    Department of Pediatrics and Child Health, Kurume University School of Medicine, Japan.

    Papers in Europe PMC
  5. 05
    Hu PY4 papers · 2004

    Edward A. Doisy Department of Biochemistry and Molecular Biology, St. Louis University School of Medicine, Missouri, USA.

    Papers in Europe PMC
  6. 06
    Singh A4 papers · 2021

    Division of Pediatric Nephrology, Department of Pediatrics, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.

    Papers in Europe PMC
  7. 07
    Strisciuglio P4 papers · 2004

    Department of Pediatrics, Faculty of Medicine, University of Reggio Calabria, Italy.

    Papers in Europe PMC
  8. 08
    Yang Y4 papers · 2023

    Division of Endocrinology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

    Papers in Europe PMC
  9. 09
    Yoshida I4 papers · 1999
    Papers in Europe PMC
  10. 10
    Almstedt K3 papers · 2009

    IFM-Department of Chemistry, Linköping University, 581 83 Linköping, Sweden.

    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). 17 trials are registered for osteopetrosis, 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.

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

Broader category: osteopetrosis

17

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 1 · after dedupe 1 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 1 · 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).

Uncertain / not reviewed (1)

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 Osteopetrosis with renal tubular acidosis — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

Likely covered — the policy lists Osteopetrosis as a category (Group 1), and this condition is a form of it. Confirm eligibility with a Centre of Excellence.

Group 1 — one-time curative treatment

Up to ₹50 lakh per patient

Financial support for treatment at notified Centres of Excellence (figures evolved from the original ₹20 lakh Group-1 ceiling).

Policy figures change. Verify current MoHFW / CoE guidance before relying on any amount. 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.

("Osteopetrosis with renal tubular acidosis" OR "Carbonic anhydrase 2 deficiency" OR "Guibaud-Vainsel syndrome" OR "Marble brain disease" OR "Mixed RTA" OR "Mixed renal tubular acidosis" OR "Renal tubular acidosis type 3" OR "Autosomal Recessive osteopetrosis, type 3" OR "CA2 osteopetrosis (disease)" OR "OPTB3" OR "autosomal recessive osteopetrosis type 3" OR "carbonic anhydrase II deficiency" OR "osteopetrosis (disease) caused by mutation in CA2" OR "osteopetrosis, autosomal recessive 3, with renal tubular acidosis" OR "osteopetrosis, autosomal recessive type 3") OR ("CA2 syndrome" OR "CA2-related")

Run this search on Europe PMC

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

"Osteopetrosis with renal tubular acidosis" OR "Carbonic anhydrase 2 deficiency" OR "Guibaud-Vainsel syndrome" OR "Marble brain disease" OR "Mixed RTA" OR "Mixed renal tubular acidosis" OR "Renal tubular acidosis type 3" OR "Autosomal Recessive osteopetrosis, type 3" OR "CA2 osteopetrosis (disease)" OR "OPTB3" OR "autosomal recessive osteopetrosis type 3" OR "carbonic anhydrase II deficiency" OR "osteopetrosis (disease) caused by mutation in CA2" OR "osteopetrosis, autosomal recessive 3, with renal tubular acidosis" OR "osteopetrosis, autosomal recessive type 3"

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

Parent-category trials query:

"osteopetrosis"

Query health: ok — strategies attempted: phrase; 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 (2003) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-26T21:11:26.759Z