Clinical Application of Massively Parallel Sequencing in the Diagnosis of Hereditary Hemolytic and Dyserythropoietic Anemias

The Hereditary Hemolytic Anemias (HHAs) are a genetically heterogeneous group of anemias characterized by decreased red blood cell (RBC) survival because of defects in hemoglobin, RBC membrane proteins or enzymes. The diagnosis of this group of disorders is complex and challenging requiring analysis of the morphology of RBCs, hemoglobin electrophoresis, and a battery of phenotypic assays. The phenotypic analysis is often problematic in transfusion dependent patients or at times of presentation with a hemolytic crisis as transfused blood or reticulocytosis confounds diagnostic testing. Molecular genetic testing has grown in popularity in the diagnosis of hereditary hemolytic anemias as it is not affected by transfusions or other clinical variables and provides additional insight into the mechanism of the disease. We have developed a Next Generation Sequencing (NGS) panel for HHA due to RBC membrane disorders and enzymopathies and congenital dyserythropoietic anemias (CDA). CDAs, although collectively rare, are included in the panel as they are occasionally misdiagnosed as hereditary spherocytosis (HS) due to their clinical characteristics of hemolysis, increased osmotic fragility, and splenomegaly albeit with inadequate reticulocytosis