Inherited metabolic disorders
Autosomal recessive malignant osteopetrosis
Also called: ARO · IMO · malignant infantile osteopetrosis · osteopetrosis · marble bone disease · Infantile malignant osteopetrosis · Autosomal recessive osteopetrosis, severe infantile form
What a donor has to do with this
For some people with this condition, a transplant using blood stem cells from an unrelated donor is part of the treatment guidelines. When a transplant is the right route and no one in the family matches, that donor comes from a registry. Not everyone with this condition has a transplant, and many never need one.
This is our reading of published transplant guidelines for this condition, not a measurement of how many people need a donor. Where a source actually counted donors, the figure and the people it counted are shown further down. Where none did, we say so rather than estimate.
What the evidence says
- Who it affects
- Typical onset/diagnosis: malignant autosomal-recessive osteopetrosis affects both sexes and is usually apparent in early infancy. Evidence: Europe/international EBMT synthesis (2024), which reports incidence near 1 per 100,000 births; no markedly enriched population was identified.
- Treatments other than a transplant
- Supportive transfusion, calcium management, infection care, and surgical/ophthalmic management — noncurative management — multiple regions — Does not restore osteoclast function in transplant-responsive genotypes.
- If a transplant is used, the cells come from
- bone marrow: used and preferred over peripheral blood in the cited matched-donor/PT-CY guidance; mobilized peripheral blood stem cells: used but ranked below bone marrow in the cited matched-donor/PT-CY guidance; umbilical cord blood: not recommended because of high graft-failure risk; dominance: bone marrow is the preferred graft source in the opened EBMT guidance
- How often the donor was unrelated
- Not reported. No source we could read states this for this condition, so we do not give a number. An estimate here would be a guess dressed as evidence.
Where this gets complicated
HCT is contraindicated or ineffective for osteoclast-extrinsic RANKL/TNFSF11 disease and may worsen primary neurodegenerative OSTM1 or some CLCN7 forms.; EBMT guidance does not recommend cord blood routinely because graft failure is high, despite published cord-blood experience.
People with this condition need donors
Joining a registry is a cheek swab and a short health form. You are contacted only if you turn out to be a possible match for someone, and you can ask questions and decline before anything else happens.
Related conditions
Others in inherited metabolic disorders. They are genuinely different diseases with different treatments — the group name is not a diagnosis.
Where this came from
- Osteopetrosis — NIH NCATS GARD, updated 2026-06
- EBMT Handbook Table 91.3: Allogeneic HCT in osteopetrosis — EBMT/Springer, 2024-04-11
- EBMT Handbook, Chapter 91: Inborn Errors of Metabolism and Osteopetrosis — EBMT/Springer, 2024-04-11