[Molecular epidemiological analysis of α- and β-thalassemia in Fujian province]

To investigate the gene prevalence and spectrum of alpha- and beta-thalassemia in Fujian province.

A total of 11 234 of neonatal cord blood samples were collected for a prevalence study of alpha- and beta-thalassemia. All subjects included in this study were registered in 9 cities of Fujian province. A complete blood count and high performance liquid chromatography (HPLC) were performed in all samples, with microcytosis (MCV≤ 79 f1 and MCH≤ 27 pg) or HPLC positive cases further studied by DNA analysis. alpha- and beta-thalassemia were determined by using gap-PCR and reverse dot blot (RDB) assays. Unknown positive samples were analyzed directly with DNA sequencing.

Of all 11 234 cord blood samples, 356 were identified as from alpha-thalassemia gene carriers, 7 deletion genotypes were identified including 236 (--SEA/ α α) cases, 67 (α 3.7/ α α) cases, 24 (alpha 4.2/alpha alpha) cases, 3 (alpha 3.7/ SEA) cases, 1 (alpha 4.2/ SEA) cases, 1 (alpha 3.7/ alpha 3.7) cases, 1 (alpha 3.7/ alpha 4.2) cases; 3 non-deletion genotypes were detected, including 7 (alpha alpha QS/ alpha alpha) cases, 3 (α α CS/α α) cases, 2 (α α WS/ α α) cases, the most common mutation was SEA/α α, which accounted for 66.29%, 148 individuals were found to have beta-hemoglobin gene mutations. 12 different mutations were identified, namely 65 IVS-2 654 (C>T) cases, 40 CD41-42(-TCTT, 12 CD17(A>T) cases, 10 -28(A>G) cases,7 CD27-28(+C) cases, 5 start codon ATG>AGG cases, 2 CD26(G>A) cases, 1 CD71-72(+A) cases, 1 IVS-1-1(G>T) cases, 1 CD43(G>T) cases, 2 -29(A>G) cases, 2 Codon 36 (-C) cases, the most common mutation was IVS-2 654(C>T) and CD41-42(-TCTT), which accounted for 70.95%. A novel beta-globin gene mutation CD36 (-C) allele was also detected. The carrier rate of thalassemia in Fujian population is 4.41%. In addition, 9 beta-thalassemia carriers were found with alpha-thalassemia mutation.

The research has revealed the type of gene mutations in alpha- and beta-talassemia in Fujian province. The beta-thalassemia mutations in Fujian province are complex, which were also obviously heterogeneous. This will significant value for screening the incidence, provide the valuable information for genetic counseling and prenatal diagnosis.