A novel four base-pair deletion within the Agamma-GLOBin gene promoter associated with slight increase of Agamma expression in adult.

We studied a Chinese family and revealed 5.4% and 3.2% fetal hemoglobin (HbF) with advantageously Agamma type in the mother and the daughter, respectively, using alkali denaturation assay and urea-Triton-acrylamide gel electrophoresis and high-performance liquid chromatography. The father's HbF was less than 0.5%. Large deletion was not observed within the beta-globin gene cluster by restriction endonuclease mapping. Characterization by the polymerase chain reaction (PCR) and DNA sequencing demonstrated the mother is a homozygote with a novel four base-pair "AAGC" (-226 to -223) deletion within the Agamma-globin gene promoter and the daughter is a heterozygote with this deletion. The deletion was not detected in the father. No any mutations were identified in the Ggamma promoter of all the subjects studied. We propose that the small deletion is associated with the slight increase of Agamma gene expression in adult. Copyright 2000 Wiley-Liss, Inc.