[Phenotypic and genotypic analysis of 45 cases with Hemoglobin Q-Thailand]

To explore hematological and molecular characteristics of Hemoglobin Q-Thailand in Huizhou area of Guangdong Province.

A total of 34 977 samples were screened by capillary and agarose gel electrophoresis. Samples suspected with HbQ strips were subjected to blood cell count and DNA sequencing. Twenty three common mutations associated with α- and β-thalassemia were identified by liquid phase chip and diversion hybridization technique.

The carrier rate of Hb Q-Thailand in Huizhou area was 0.13%. Pedigree analysis indicated that the Hb Q-Thailand allele is linked with a leftward single a-globin gene deletion (-α^4.2). Hematological index (HGB, MCV, MCH, HbA, HbA₂, HbQ) of 45 heterozygous carriers of Hb Q-Thailand were (130.25±17.37) g/L, (79.81±4.97) fl, (26.38±1.48) pg, (71.37±5.07)%, (1.65±0.45)%, (26.87±4.95)%, respectively. A statistical difference was also found in their hematological index of HbA and HbA₂ compared with 408 heterozygous carriers of -α^4.2 mutation (P<0.05).

Hb Q-Thailand has a high detection rate in Huizhou area. The allele is mainly in a heterozygous status and linked with -α^4.2. The Hb Q strip can be detected by hemoglobin electrophoresis. When combined with other types of thalassemia, the heterozygotes will show unique hematological parameters.