Chromosome 22q11.2 deletion presenting with immune-mediated cytopenias, macrothrombocytopenia and platelet...

To report a case of chromosome 22q11.2 deletion presenting with large platelets, platelet dysfunction, immune-mediated thrombocytopenia and neutropenia, in addition to other features of the disease.

The patient presented in the neonatal period with tetralogy of Fallot, subtle dysmorphic features and thrombocytopenia. Fluorescent in situ hybridization analysis confirmed the diagnosis of chromosome 22q11.2 deletion. Further investigations showed immune thrombocytopenia and neutropenia in addition to reduced expression of platelet GPIb and abnormal platelet aggregation studies. CD4:CD8 ratio was reversed. His cardiac abnormality was successfully corrected surgically. He had mild recurrent bacterial infections. Recurrent epistaxis was becoming increasingly more severe, and he had cognitive developmental and speech delay. His serum calcium, phosphorus and parathormone have remained normal.

Immune thrombocytopenia can coexist with macrothrombocytopenia and platelet dysfunction in chromosome 22q11.2 deletion and may present with significant bleeding episodes.