A Case of Hereditary Spherocytosis Misdiagnosed as Pyruvate Kinase Deficient Hemolytic Anemia

Background Hereditary spherocytosis (HS) and pyruvate kinase (PK) deficiency are the most common causes of congenital hemolytic anemia. We describe a case of HS with defective PK activity initially misdiagnosed as PK deficiency. Methods Hematologic investigation, SDS-PAGE analysis of red cell membrane proteins and sequencing of the PKLR gene were performed. Results The molecular characterization of the PKLR gene showed a heterozygous mutation 994G > A (Gly332Ser) associated with the promoter substitution -148C > T, whose role in the pathophysiology of PK deficiency is debated. Further investigations revealed spectrin deficiency; the family study demonstrated that the hemolysis was exclusively attributable to HS. Conclusions The present case pinpoints to the need for extensive family investigations to correctly diagnose chronic hemolytic anemia, in particular when molecular characterization does not fully explain the clinical phenotype.