Somatic mutation in RUNX1 underlies mucocutaneus inflammatory manifestations

Dear Editor, Advances in sequencing technologies have improved diagnostic processes in clinical medicine and have provided molecular diagnosis in many cases with Mendelian disorders, including monogenic immunological and inflammatory disorders [1–3]. In general, the impact of monogenic events on rheumatic diseases and inflammatory disorders is limited; such disorders have been thought to be caused by multifactorial inherited and environmental factors. Recently, however, several intensive studies revealed the pathogenic importance of somatic mutations in specific genes, including UBA1 in adult-onset autoinflammatory syndrome [4] and NFKBIZ in ulcerative colitis [5], suggesting that somatic events contribute more than was thought to rheumatic and inflammatory disorders. Here, we report the case of a child with a somatic RUNX1 mutation who developed atypical mucocutaneous inflammatory symptoms, followed by transformation to acute myeloid leukaemia (AML) with myelodysplastic changes 2 years later. This study was conducted in accordance with the...