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.