Atypical Presentation of UBE2T-Related Fanconi Anemia With Immune-Mediated Thrombocytopenia and Hematopoietic Somatic Mosaicism: A Case Report.

Fanconi anemia (FA) is a genetically heterogeneous disorder of chromosome instability leading to bone marrow failure (BMF) and other manifestations. We report a case of FA in which two atypical features initially obscured the diagnosis: the presence of T cell-mediated thrombocytopenia, and somatic mosaicism leading to normal chromosome breakage studies in blood. The diagnosis was ultimately established after trio exome sequencing identified biallelic variants in UBE2T, consistent with one of the rarest FA subtypes. This case adds to sparse literature on UBE2T-FA and immune cytopenias in FA, and highlights the role of genomic testing in the diagnostic evaluation of BMF.