Karyotype was abnormal, with unbalanced 1q JTs to the short arms of acrocentric chromosomes 14 and 21, leading to gain of 1q.<h4>Conclusions</h4>Our patient had MDS with pathogenic mutations of the <i>RUNX1</i>, <i>SRSF2</i>, <i>ASXL1</i>, and <i>TET2</i> genes and developed 1q JTs at the time of progression from MDS to AML. The gene discussed is TET2; the disease is myelodysplastic syndrome.