HAEMOGLOBIN H DISEASE AMONG CHINESE RESIDENTS OF TAIWAN

Intrathoracic extramedullary hematopoietic tumor in hemoglobin H disease

We report a Chinese patient with hemoglobin H (Hb H) disease who developed intrathoracic extramedullary hematopoiesis (EMH) 17 years following splenectomy for a blunt abdominal injury. The patient initially presented with extreme hyperbilirubinemia and multiple intrathoracic tumors. Hb H disease was diagnosed after investigation, and the marked jaundice, which declined gradually after supportive treatment, was attributed to his chronic hemolysis superimposed on an acute hepatitis C virus infection. A biopsy of the intrathoracic tumors revealed an EMH. Intrathoracic EMH, which is usually encountered in patients with beta-thalassemia and hereditary spherocytosis, has never been reported in Hb H disease. In areas where thalassemia is prevalent, EMH should be considered in the differential diagnosis of patients who have chronic anemia with asymptomatic intrathoracic tumor to avoid unnecessary surgical interventions.

Prenatal diagnosis of Chinese homozygous alpha-thalassaemia 1 and haemoglobin H disease by analysis of alpha- and phi zeta-globin genes in chorionic villi and amniocytes

Eighty-eight high-risk pregnancies, 81 for homozygous alpha-thalassaemia 1 and 7 for haemoglobin (Hb) H disease, were collected in this study. Chorionic villus sampling (CVS) was done in 63 cases and amniocentesis in 25 cases to obtain fetal cells. Southern blotting and DNA hybridization with alpha- and phi zeta-globin gene probes were used to determine the alpha-globin gene status. In two non-informative families with non-deletional mutations, DNA analysis failed to rule out the affected condition, and fetal blood sampling (FBS) and Hb electrophoresis were used for the final diagnosis. In the 81 fetuses at risk for homozygous alpha-thalassaemia 1, 17 (13 by CVS and 4 by amniocentesis) were affected, 30 were alpha-thalassaemia 1 heterozygotes, 19 were normal, and the remaining 15 were either normal or heterozygous. In the seven fetuses at risk for Hb H disease, one was normal, three were alpha-thalassaemia 1 heterozygotes, two were alpha-thalassaemia 2 heterozygotes, and one was affected with Hb H disease and developed hydrops fetalis. DNA analysis on fetal cells enabled us to diagnose prenatally severe alpha-thalassaemias, to prevent the birth of infants with Hb H disease, and to minimize maternal obstetrical complications from harbouring a fetus with Hb Bart's hydrops fetalis.