Doctors have successfully treated India's first known case of MYSM1-related bone marrow failure syndrome (BMFS4), an extremely rare genetic condition, using a half-matched (haploidentical) bone marrow transplant.
What is MYSM1-Related Bone Marrow Failure?
MYSM1-related bone marrow failure is an extremely uncommon hereditary condition resulting from mutations in both alleles of the MYSM1 gene. There have been fewer than 20 cases reported around the world, which makes diagnosis and treatment very difficult.
The Patient's Journey
The patient, a 12-year-old boy, had symptoms since he was a baby, including severe anemia that made him need regular blood transfusions. At first, doctors thought he might have Diamond–Blackfan anemia, and he did respond to steroid treatment when he was young. However, when he was 11, his health worsened, with more anemia and low platelet counts, leading to further testing.
Dr. Arun Singh Danewa, Senior Consultant in Pediatric Hematologic Oncology & Bone Marrow Transplant (Unit II) at Artemis Hospitals, explained: "This was a very rare and challenging case. The child had an unusual genetic condition affecting the bone marrow, and such cases are extremely uncommon worldwide. While bone marrow transplant is the only curative option, the difficulty here was that we could not follow a standard approach. Because the disease is driven by a specific genetic defect, we had to carefully modify the transplant conditioning regimen to make it both safe and effective for this child. Balancing the risk of toxicity with the need for successful engraftment required very close planning and monitoring."
Advanced diagnostic testing, including next-generation sequencing, revealed a MYSM1 gene mutation and confirmed bone marrow failure, leading to the diagnosis.
The Transplant Procedure
On January 31, 2026, the patient received a haploidentical stem cell transplant from his father because his condition was worsening. A carefully planned, low-intensity conditioning program was used to ensure successful engraftment and lower the risk of side effects.
The transplant was highly successful, with blood cells starting to recover within 12 to 14 days. By day 30, there was 100% donor chimerism, meaning the recipient's body had fully accepted the donor cells. There were no major complications. The procedure required a three-week hospitalization in a stringent, sterile, high-tech isolation unit. The boy is now an active outpatient, coming in only for routine check-ups as his new marrow settles in.
Significance and Challenges
This case is particularly significant due to the rarity of the condition. Doctors emphasized that MYSM1 deficiency can resemble other inherited bone marrow failure syndromes in early stages, making diagnosis difficult without advanced genetic testing. The transition from isolated anemia to multilineage cytopenia illustrates the disease's progression over time.
This case demonstrates that haploidentical transplantation, combined with post-transplant cyclophosphamide, can be an effective treatment for patients, especially when matched donors are unavailable.
