OBJECTIVETo analyze genotypic profiles and understand the relationship between the genotype and phenotype of Hb H disease in Guangxi province.

METHODSHematologic and Hb analyses on the cases were performed to detect their alpha thalassemia genotypes using PCR method and DNA sequencing.

RESULTSAn unusual case was identified in one of the 298 patients with Hb H disease diagnosed in the First Affiliated Hospital of Guangxi Medical University from October 2002 to November 2003. The 25-year-old male patient, a native of Yulin in Guangxi province, had had jaundice and splenomegaly since childhood, and he had never received blood transfusion. Hematologic examinations revealed his hemoglobin 107 g/L, RBC 4.9+10(12) g/L, MCV 76.2 fl, MCH 21.8 pg, MCHC 287 g/L, HCT 0.373, reticulocyte 3%. Hb analysis showed the level of Hb H + Hb Bart's 34.41%. PCR and DNA sequencing confirmed the genotype of a deletion at codon 30 of alpha2 globin gene and SEA alpha-thalassemia-1.

CONCLUSIONThis unusual case had no anemia, but had higher level of Hb H and Hb Bart's when compared to those non-deletional Hb H disease cases such as Hb CS-H, HbQS-H and alpha2 codon 31 mutation combined with SEA alpha-thalassemia-1 previously reported in mainland China. The discovery and recognition of this gene mutation and related genotype and phenotype is of importance to the genetic counseling and prenatal diagnosis in Guangxi province where the incidence of alphathalassemia is very high.