Genetic diagnosis for congenital hemolytic anemia

Congenital hemolytic anemia is a group of monogenic diseases presenting with anemia due to increased destruction of circulating erythrocytes. The etiology of inherited anemia accounts for germline mutations of the responsible genes coding for the structural components of erythrocytes and extra-erythrocytes. The erythrocyte abnormalities are classified into three major disorders of red cell membrane defects, hemoglobinopathies, and red cell enzymopathies. The extra-erythrocyte abnormalities, typified by consumption coagulopathy and intravascular hemolysis, include Upshaw-Schulman syndrome and atypical hemolytic uremic syndrome. The clinical manifestations of congenital hemolytic anemia are anemia, jaundice, cholelithiasis and splenomegaly, while the onset mode and severity are both variable. Genetic overlapping of red cell membrane protein disorders, and distinct frequency and mutation spectra differing among races make it difficult to understand this disease entity. On the other hand, genetic modifiers for the phenotype of β-globin diseases provide useful information for selecting the optimal treatment and for long-term management. Recently, next generation sequencing techniques have enabled us to determine the novel causative genes in patients with undiagnosed hemolytic anemias. We herein review the concept and strategy for genetic diagnosis of inherited hemolytic anemias.