RÉSUMÉ
In Thailand, the most common cause of chronic hemolytic anemia is thalassemia hemoglobinopathy. We report here a 10-year-old girl with pyruvate kinase (PK) deficiency who was initially diagnosed to have Hb H disease, like her sister. The patient had a history of neonatal jaundice which required blood exchange transfusion twice and phototherapy. She became anemic and regular blood transfusion was required since the age of 2 1/2 months. She was very anemic compared to her sister and was transfusion dependent. Besides, she never had red cell inclusion bodies, thus re-evaluation was performed. The diagnosis of red cell pyruvate kinase deficiency and the exclusion of Hb H disease was achieved after cessation of blood transfusion for 3 months. The family study also confirmed the diagnosis. The patient is now on high transfusion and iron chelation. She is doing well with mild splenomegaly.