Three cases of the hemoglobin G-Chinese variant detected in patients of southern Chinese origin.

Hemoglobin (Hb) G-Chinese [α30 (B11) Glu↷Gln], also known as Hb G-Honolulu, Hb G-Hongkong or Hb G-Singapore, was first identified in a Chinese woman in Singapore, and was subsequently observed in several Chinese families. This Hb variant results from a GAG↷CAG mutation at codon 30 of the α-globin gene. The aim of the present study was to identify the Hb G-Chinese mutation in three Cantonese individuals. The presence of the Hb variant was confirmed by cellulose acetate electrophoresis. DNA analysis based on the polymerase chain reaction (PCR) and sequencing were conducted to confirm the presence of the mutation in the α-globin gene. A G↷C substitution at codon 30 of the α2-globin gene was observed. According to a previous study, the G↷C substitution in Hb G-Chinese creates a PstI restriction site; we amplified the α2-globin gene, then digested the PCR products with PstI. The results indicated that only the PCR product of Hb G-Chinese α2-globin was cut by PstI. The digestive products were 120 and 730 bp, respectively. Therefore, we determined that the three cases were of the heterozygous Hb G-Chinese variant.