(Out of hours: 0844 840 0103)

An alternative form of a gene (one member of a pair) that’s located at a specific position on a specific chromosome and determines a distinct trait that can be passed on from parents to children.

A transplant using cells taken from a healthy donor and given to a patient. Sometimes called a graft.

A transplant using the patient’s own cells. Doctors collect their stem cells, remove their diseased cells, then return the stem cells to the patient.

A transplant using the patient’s own ’cleaned up’ stem cells.

British Bone Marrow Registry (the NHS’s bone marrow register).

A term for cancers that affect the blood, bone marrow and lymphatic system. There are three main kinds of blood cancer – leukaemia, lymphoma and myeloma.

Found in the centre of all large bones. Blood stem cells are produced there.

The process of taking the bone marrow or peripheral blood stem cells from the donor. Doctors can do this in two ways: via bone marrow harvest

British Society of Blood and Marrow Transplantation.