KIT protein is a tyrosine kinase receptor that is responsible for activating phosphorylation cascade in various transcription factors.[9] Researches have shown KIT D816V mutation, which was identified in more than 80% of patients with SM, induced autophosphorylation of KIT receptor.[10] In addition, the mutation of AT-rich interaction domain 1A (Arid1a) was found in the patient. The gene discussed is KIT; the disease is systemic mastocytosis.