The t(X;5)(q13;q33) Translocation in Myeloid Neoplasms Is Preferentially Associated With Chronic Myelomonocytic Leukemia: A Report From the Groupe Francophone de Cytogénétique Hématologique

t(X;5)(q13;q33) is a very rare but recurrent translocation observed in hematological malignancies. Only two myeloid cases have been reported in the literature to date. In one case, it was demonstrated that the t(X;5) involves the inactive X chromosome and is associated with silencing of autosomal genes located on 5q. Here, we report four additional cases. Overall, t(X;5) is frequently associated with chronic myelomonocytic leukemia (CMML) (4/6 cases, 67%) and may have functional consequences similar to those of del(5q). In contrast to del(5q) in CMML, which is often associated with a complex karyotype, t(X;5) is most often observed as an isolated abnormality and may define a distinct subgroup with favorable genetic features. Additional cases and functional studies are needed to confirm our observations.