Williams syndrome and mature B-Leukemia: A random association?

Williams syndrome (WBS) is a rare neurodevelopmental disorder with specific phenotypic characteristics and cardiac abnormalities, but is not considered as a cancer predisposing condition. However, in rare cases, malignancies have been described in patients with WBS, with hematologic cancer (mainly Burkitt Lymphoma and Acute Lymphoblastic Leukemia) as the most represented. We report here the case of a boy with WS and B-NHL. This is the unique case within the large cohort of patients (n = 117) followed in our institution for long time (mean clinical follow-up, 13 years). We herewith propose that the BCL7B gene, located in the chromosomal region commonly deleted in Williams syndrome, could potentially have a role in this particular association.