Bone marrow failure

Bone marrow failure happens when the bone marrow cannot make enough new blood cells. NHLBI describes aplastic anemia, the best-known form, as a rare but serious blood condition. Low red cells can cause tiredness, low white cells raise the risk of infection, and low platelets cause bruising or bleeding. Marrow failure can be acquired during life or inherited. NCI researchers describe the inherited bone marrow failure syndromes as a group of rare genetic blood disorders in which there is usually some form of aplastic anemia.

NHLBI says the most common cause is the immune system attacking the blood-forming stem cells in the bone marrow. Some medicines, such as those used in chemotherapy, and exposure to toxins or chemicals can also cause it. Aplastic anemia is inherited only in rare cases. PNH, a related condition, is also acquired rather than inherited. It is usually caused by a new change in the PIGA gene in some blood-forming cells.

It can. Among people with aplastic anemia, a 2026 review estimates that about 11 to 20 in 100 later develop MDS or acute myeloid leukemia (AML). NCI researchers say people with inherited marrow failure syndromes have a very high risk of leukemia or certain solid tumors. MedlinePlus Genetics, for example, puts the chance of certain cancers at 10 to 30 in 100 for people with Fanconi anemia. It says about 20 in 100 people with severe congenital neutropenia develop MDS or leukemia, often during the teenage years. That is one reason for regular checkups.

Blood transfusions support people while treatment works. The two main treatments are immune-calming medicines and a donor stem cell transplant. The medicines are usually horse antithymocyte globulin (ATG), cyclosporine and eltrombopag. A 2026 review says younger people with a matched brother or sister are considered for a transplant first. People over 40, or without a matched sibling, usually start with the medicines. Guidelines differ on unrelated donors. A 2024 U.S. guideline from ASTCT favors a transplant from a matched unrelated or half-matched donor over the medicines for children and adults with no matched relative. The 2025 European EBMT recommendations say a matched unrelated donor transplant can be a first choice for people under 18. This applies when it can happen within about two months of diagnosis. Otherwise, they advise it after one course of the medicines has not worked.

Because it changes the plan. A 2026 review says the immune-calming treatment used for acquired aplastic anemia generally does not work in inherited syndromes. The chemotherapy used to prepare for a transplant (conditioning) also differs, because some inherited conditions make the body more sensitive to it. And possible family donors must be checked carefully, so a transplant does not bring in the same genetic problem. For example, the Fanconi Cancer Foundation’s care guidelines say every brother and sister of a person with Fanconi anemia should have a chromosome breakage test. This matters most when a relative may become a donor.

No, but they are closely linked. PNH is an acquired disorder in which some blood cells lack protection from complement, part of the immune system. Red cells are destroyed early, and dangerous clots can form. MedlinePlus Genetics says some people who have or have been treated for aplastic anemia develop PNH. Small groups of PNH cells are found in about 40 to 60 in 100 people with aplastic anemia. PNH is usually treated with complement-blocking medicines. European EBMT recommendations say a donor transplant is generally not recommended for classic PNH when these medicines are available. It remains an option when PNH comes with severe marrow failure or turns into MDS or AML.

In many cases, yes. When there is no matched brother or sister, a well-matched unrelated volunteer is an established donor for severe aplastic anemia in both U.S. and European guidelines, although they differ on timing. For inherited syndromes, relatives are checked first, because a brother or sister can carry the same condition. U.S. guidelines advise HLA typing and a first search of the NMDP Registry at diagnosis whenever a donor transplant may be needed. Joining a registry cannot promise a match for any one person.