Mastocytosis - Causes of mastocytosis

The exact cause of mastocytosis is unknown, but genetic mutations are known to be involved.

A genetic mutation occurs when normal instructions carried in certain genes become "scrambled". This results in some of the body’s processes not working normally.

The kit mutation

Most people with cutaneous or systemic mastocytosis have a genetic mutation known as the kit mutation. It makes their mast cells more sensitive to the effects of a type of protein called stem cell factor (SCF).

SCF plays an important role in stimulating the production and survival of certain cells, such as blood cells and mast cells, inside the bone marrow. Bone marrow is the soft, jelly-like tissue found in the hollow centre of all large bones. It contains stem cells that are capable of producing specialist cells, such as mast cells.

When the bone marrow is exposed to SCF, it produces more mast cells than the body can cope with. This leads to symptoms of mastocytosis.

In a few cases of mastocytosis, it appears that the kit mutation is inherited (passed down through families). However, in most cases, the mutation is spontaneous (it occurs for no apparent reason).