12-year-old with ultra-rare genetic disorder recovers after life-saving transplant

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.

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, 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. But when he was 11, his health got worse, with more anemia and low platelet counts, which led to more tests.

Dr Arun Singh Danewa, Senior Consultant in Pediatric Hematologic Oncology & Bone Marrow Transplant (Unit II), Artemis Hospitals, "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, showed that there was a MYSM1 gene mutation and that the bone marrow was failing, which confirmed the diagnosis. On January 31 2026 the patient received a haploidentical stem cell transplant from his father because his condition was getting worse. A carefully planned and low intensity conditioning program was used to make sure that the engraftment worked and to lower the risk of side effects.

The transplant was very successful, and blood cells started to come back within 12 to 14 days. There was 100% donor chimerism by day 30 which meant that the recipient's body had fully accepted the donor cells. There were no major problems. The procedure necessitated a three-week hospitalization in a stringent sterile, high tech isolation unit. He is no longer a patient in a room but a active boy in the OPD coming in only for routine check-ups as his new marrow settles in. This case is particularly significant due to the rarity of the condition.

Doctors stressed that MYSM1 deficiency can look a lot like other inherited bone marrow failure syndromes in their early stages, which can make it hard to diagnose 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, in conjunction with post-transplant cyclophosphamide, can be an effective treatment for patients, particularly in the absence of matched donors.