Welcome to MastoConnect,

Your Guide to Understanding Systemic Mastocytosis

Whether you’re living with systemic mastocytosis (SM) or caring for someone who is, MastoConnect is a place created with you in mind. Here, you can explore helpful information, find practical tools and resources, and connect with a community of people who understand.

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It’s time to take the guesswork out of SM

SM is a rare disease caused by an excess of abnormal mast cells (a type of immune cell) building up in the body. With various symptoms, treatment options, and complex conversations, it can be overwhelming to tackle.1-3

We’re here to help you make sense of that. Get started by understanding your diagnosis, exploring ways to manage SM, or connecting with communities and resources.

SM is a rare disease that affects up to 1 in ~5,000 adults4-7

A recent, independent epidemiology study shows that SM may be more common than previously thought.4‑7

  • Common symptoms of SM can include skin reactions, GI issues, and fatigue, and can vary across time, but the root cause for most people is a small change in a part of their DNA.8-10
  • This specific change in DNA, known as the KIT D816V mutation, is found in the KIT gene.9‑11

SM can impact work, productivity, and quality of life7,12

A 100-item survey* of 56 US adults with a self-reported SM diagnosis revealed widespread challenges—participants reported disruptions to daily life, including medical disability, symptom burden, and work-related impairment. These findings highlight the profound effect SM can have on everyday life.

Kristine†

Living with ISM

"There are many challenges and things that I've had to give up that I've enjoyed doing. Many things that I can't eat, it's not safe."

Based on a recent TouchStone SM Patient Survey—sponsored by Blueprint Medicines.

This individual receives compensation from Blueprint Medicines for sharing their experience living with systemic mastocytosis through the Blueprint Medicines SM Ambassador Program.

Learn about SM in more detail

Get more information

Learn what’s next for diagnosed patients

Explore next steps

Learn what’s possible from doctors and the SM community

Hear from healthcare professionals and people living with SM at an upcoming event. You’ll learn about SM and its impact, find ways to manage it, and more.

Find an event
  1. Li JY, et al. Cancers. 2023;15(23):5626.
  2. Systemic mastocytosis. Orphanet. Accessed January 14, 2026. https://www.orpha.net/consor/​www/cgi-bin/OC_Exp.php?lng=EN&Expert=2467
  3. Sperr WR, et al. Lancet. 2019;6(12):e638-e649.
  4. Bergström A, et al. Acta Oncol. 2024;63:44-50.
  5. Van Doormaal JJ, et al. J Allergy Clin Immunol. 2013;131(5):1429-1431.
  6. Brockow K. Immunol Allergy Clin North Am. 2014;34(20):283-295.
  7. Cohen SS, et al. Br J Haematol. 2014;166(4):521-528.
  8. American Academy of Allergy, Asthma & Immunology. Accessed January 14, 2026. https://www.aaaai.org/conditions-treatments/related-conditions/systemic-mastocytosis
  9. Ungerstedt J, et al. Cancers (Basel). 2022;14(16):3942.
  10. Garcia-Montero AC, et al. Blood. 2006;108(7):2366-2372.
  11. Kristensen T, Vestergaard H, Bindslev-Jensen C, et al. Am J Hematol. 2014;89(5):493-498.
  12. Mesa RA, et al. Cancer. 2022;128(19):3691-3699.