Causes of MCAS

Identifying the causes of MCAS is not at all simple. Mast cell disease is a disease of inappropriate mast cell activation. As mentioned before, Mast Cell Activation Disease MCAD is an umbrella term covering Mast Cell Leukaemia, Mastocytosis and Mast Cell Activation Syndrome – MCAS.

Mast cell proliferation and inappropriate activation is seen in Mast Cell Leukaemia, Systemic Mastocytosis and Cutaneous Mastocytosis, but not in MCAS. In MCAS there is little or no mast cell proliferation, but major inappropriate mast cell activation. This activation triggers release of a myriad of potent mediators, only a few of which can currently be measured in clinical (as opposed to research) laboratories. The complex and widely different presentation of MCAS is simply the result of the wide variety of mediators that can potentially be released.

There is a definite genetic link to MCAD. The KIT D816v mutation is frequently found in systemic mastocytosis. However, this mutation is rarely found in MCAS. Instead, there is increasing evidence that many patients with MCAS have a wide array of other KIT mutations. This is an incredibly complex area which is far from being fully understood at present, and is currently the subject of intense research. With increasing understanding, the causes of MCAS will become clearer.

For more information on MCAS please do not hesitate to get in touch with Dr Deering through our appointments page.

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