Gene Therapy Clinical Trial for Infantile Malignant Osteopetrosis (IMO)

Infantile Malignant Osteopetrosis is a rare severe autosomal recessive genetic disorder characterized by deficient osteoclast development and/or function.


It results in defective bone resorption & growth.
Symptoms manifest soon after birth or in early infancy


Incidence of IMO is 1/250,000 and if untreated has a fatal outcome1

How is IMO diagnosed?³

IMO can be diagnosed during check-ups in the weeks and months after birth

Photo of a baby


  • History: difficulty feeding, excessive crying and rhinitis
  • Exam:  hypertelorism, gum thickening, pallor


  • abnormally high bone density
  • decreased marrow space
  • mask sign on skull film
Image of xrays


  • CBC with differential:  anemia, erythroblasts & immature WBC


  • TCIRG1 gene mutation

Who is eligible to participate in the IMO gene therapy clinical trial?

Pediatric patients ≥1 month of age with documented TCIRG1 mutation

Patients for whom a hematopoietic stem cell transplantation (HSCT) with an HLA-identical sibling donor is either unavailable or unfeasible

Medically fit to undergo transplantation with myeloablative conditioning

What does participation in the IMO gene therapy clinical trial involve?

There are 3 key steps that take place during the trial:

Patient Laying In Bed
  • Blood stem cells are taken from the patient
  • This takes ~ 5 days in the hospital
  • Therapeutic gene is inserted into the patient’s own cells  at a lab
  • This takes 1-2 months.  Patients will come back to hospital once this process is complete.
  • Patients will receive a drug called busulfan to help get body ready to receive the gene therapy (~ 4 days)
  • Finally, patients receive gene therapy product and will be kept in the hospital for ~ 1 month to closely monitor disease & treatment effects

Where will the IMO gene therapy clinical trial be taking place?

University of California, Los Angeles (UCLA) in Los Angeles, California, USA

Learn more about US site

How much will it cost to participate in the trial?

Financial support, including travel arrangements and housing accommodations for patients and a family member, both for the treatment and follow-up visits, will be provided.

This will also include assistance with passports, medical visas and translation services for patients and families if these are needed.

Where can I get more information about the IMO gene therapy clinical trial?


  1. Stark Z, Savarirayan R. Osteopetrosis. Orphanet J Rare Dis. 2009;4:5. Published 2009 Feb 20. doi:10.1186/1750-1172-4-5
  2. Villa, A., Guerrini, M.M., Cassani, B. et al. Infantile Malignant, Autosomal Recessive Osteopetrosis: The Rich and The Poor. Calcif Tissue Int 84, 1 (2009).
  3. Essabar L, Meskini T, Ettair S, Erreimi N, Mouane N. Malignant infantile osteopetrosis: case report with review of literature. Pan Afr Med J. 2014;17:63. Published 2014 Jan 27. doi:10.11604/pamj.2014.17.63.3759