OBJECTIVETo study the characteristics of genotype spectrum and hematologic parameters in children with HbH disease in the North Guangxi region.

METHODSHbH disease was identified by clinical manifestations, routine blood tests and hemoglobin electrophoresis in 166 children who came form the North Guangxi region. Genotypes were determined by Multi-PCR combined with PCR reverse dot blot. DNA sequencing was used when the genotype could not be identified by regular methods.

RESULTSOf the 166 children with HbH disease, 8 genotypes were identified: --SEA/-α3.7 (82 cases), --SEA/-α4.2 (40 cases), --SEA/αCSα (38 cases), --SEA/αQSα (1 case), --SEA/αWSα (1 case), --SEA/αCD43/44 (-C) α (1 case), --SEA/-α3.7 plus CD17 (A→T) (1 case) and --SEA/-α4.2 plus CD41-42(-TTCT) (1 case). One case was confirmed as the heterozygote of --SEA and an unknown mutation. In the 134 cases with complete medical data, 2 had normal hemoglobin levels, 36 manifested mild anemia, 90 manifested moderate anemia, and 6 (genotype: --SEA/αCSα) showed severe anemia because of the coexistence of infection. Children with the genotype of --SEA/-α3.7 (69 cases), --SEA/-α4.2 (31 cases) and --SEA/αCSα (34 cases) had hemoglobin levels of 62-120, 69-127 and 34-110 g/L respectively. The hemoglobin level in the --SEA/αCSα group was significantly lower than in the deletional HbH disease group (genotypes: --SEA/-α3.7 and --SEA/-α4.2 ) (P<0.05). In contrast, MCV levels in the --SEA/αCSα group were significantly higher than in the deletional HbH disease group (P<0.05).

CONCLUSIONSThe genotype spectrum of HbH disease is diverse in the North Guangxi region. Deletional genotype is prevalent. The disease is heterogeneous. The children with --SEA/αCSα HbH disease have severer anemia and higher MCV levels than those with deletional HbH disease.