Just wondering...What other pre-exsisting conditions have occured w/ MCD?? For example....multiple surgergies, diabetes, etc...
Still trying to get the answer of what causes our immune system to go haywire and over produce mast cells..
I have not had genetic test done yet, and I know right now the belief is that it is a genetic abnormality.
All I know is that for 41 Years I was healthy and then all of sudden ....disaster.

Mastocytosis is not a genetic disease. (Genetic meaning a disease that is passed from parents to children) But mastocytosis, in most cases, is "driven" by an abnormality in a gene, and the abnormality develops later than conception.

The gene is called KIT, and it tells the body how to make what we call the kit receptor, a protein found on mast cells and several other kinds of cells. When a mast cell-producing cell in the bone marrow develops this mutation (for unknown reason/s), it then produces mast cells that are continuously primed for activation and that fail to recognize signals to die. That is the cause of mastocytosis in most people. A few people, in whom mastocytosis is inherited and passed on from parents to children, do not have an activating mutation of KIT, and we don't know what causes their mastocytosis.

Mast cell activating syndrome, though, is not associated with a mutation of the kit receptor. The diagnosis of MCAS is descriptive but doesn't give us any clues to why mast cells in those people are more active than in others. People with MCAS may have a normal number of mast cells, or they may have a slightly elevated mast cell burden.

Your history of suddenly having symptoms at the age of 41 points most likely to an autoimmune cause of your mast cell activation. Do other members of your family have autoimmune diseases, such as thyroid disease, diabetes, lupus, etc?

Autoimmunity is present in many people with MCAS, so those people may also have other autoimmune diseases.

I have a family history of Autosomal Dominate Polycyctic Kidney Disease, type I and type II diabetes, Thyroid disease and autoammune deases.  I have struggled with ear infections, learning disabilities, anxiety disorders, depression, unknown anaphalxic reactions to who knows what.  I have all kinds of allergies.  When I started reading about Mast Cell Activation, I had almost every symptom listed.  Although, I have never fainted, but I have had episodes where I have lost time.  I've been told I just stare, but I do not have seizures, so I don't know what that is about.  One strange symptom I have that I have not read is pain in my bones.  I sometimes feel like my bones itch and almost burn.  Does anyone else have this?  
Sorry for rambling.  I'm a new and excited to read stuff that I'm realating to.  I'M NOT A FREAK AFTER ALL>