Atypical hemoglobin H disease in a Thai patient resulting from a combination of alpha-thalassemia 1 and hemoglobin Constant Spring with hemoglobin J Bangkok heterozygosity (original) (raw)

A case of hemoglobin H disease in combination with hemoglobin Constant Spring and a b-globin chain variant is reported in a 3-yr-old Thai girl. On routine cellulose acetate electrophoresis, one abnormal band in addition to the hemoglobins A, A 2 , H, Bart's and Constant Spring was detected. The amount of this abnormal band movement towards more anodic to the hemoglobin A was 35.7%. DNA analysis of the a-globin gene cluster by polymerase chain reaction (PCR) revealed a combination of defects caused by the SEA-type a-thalassemia 1 and the a-Constant Spring gene. Analysis of b-globin gene by PCR and DNA sequencing also detected the heterozygosity for the GGC-GAC mutation at codon 56, leading to a substitution of aspartic acid for glycine resulting in the hemoglobin J Bangkok. The hematologic data of this unusual case of hemoglobin H disease are presented and compared with two compound heterozygotes for hemoglobin J Bangkok and a-thalassemia 1 found in the patient's father and grandfather. A simple DNA assay based on an allele-specific PCR for rapid diagnosis of the hemoglobin J Bangkok is also described.