[Association Analysis between Genotype and Phenotype of α,ß-Thalassaemia Carriers in Huizhou Area of Guangdong Province].

OBJECTIVE: To analyze the prevalence, genotype distribution and hematological characteristics of α,ß-thalassaemia carriers in Huizhou area of Guangdong Province. METHODS: 10 809 carriers of simple ß-thalassaemia and 1 757 carriers of α,ß-thalassaemia were enrolled as our study cohort. The hematological parameters were detected by automated blood cell counters and automatic capillary electrophoresis. Suspension array technology, gap-polymerase chain reaction (gap-PCR) and PCR-reverse dot blot were used for the genotyping of thalassaemia carriers. RESULTS: The prevalence of α,ß-thalassaemia in Huizhou area of Guangdong Province was 1.99%. A total of 62 genotypes were detected, and the most prevalent genotype was --SEA/ αα, ßCD41-42/ ßN (19.29%), the next was --SEA/ αα, ßIVS-II-654/ ßN (16.73%). Significant differences in mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) were found between different genotype groups for simple ß-thalassaemia and α,ß-thalassaemia. Violin plots showed that carriers with co-inheritance of ß-thalassaemia and mild α-thalassaemia expressed the lightest anemia, and carriers with co-inheritance of ß-thalassaemia and hemoglobin H (Hb H) disease expressed the most severe anemia. CONCLUSION: There is a high prevalence of α,ß-thalassaemia in Huizhou area of Guangdong Province. Because of the lack of specific hematological makers for diagnosis of α,ß-thalassaemia, it is necessary to distinguish it from simple ß-thalassaemia by genotyping of α- and ß-thalassaemia in order to correctly guide genetic counseling and prenatal disgnosis.

Genetic counseling and prenatal decision for hemoglobin H disease caused by the rare α2 codon 30 (-GAG) (HBA2: c.91_93delGAG) mutation and the SEA deletion: Case series study.

OBJECTIVE: We report a rare mutation on the α2-globin gene, HBA2: c.91_93delGAG and its potential functions. CASE REPORT: We mainly described four patients with hemoglobin (Hb) H disease caused by the rare mutation and the SEA deletion but diversity in clinical presentation. Two had survived to adulthood with normal physical and mental development, except for mild anemia. However, two were children, who had more severe clinical manifestations. One child had developmental disorders of speech and language and mild growth retardation, and the other child suffered from severe hemolytic crises precipitated by infection and received blood transfusion. CONCLUSION: This study is of great significance for clinicians to provide genetic counseling to couples at-risk of having offspring with Hb H disease and let them make the pregnancy decision, particularly reduce the occurrence of severe Hb H disease.