Abstract
BackgroundHemoglobinopathies are the most common inherited diseases in southern China. However, there have been only a few epidemiological studies of hemoglobinopathies in Guangdong province.Materials and MethodsPeripheral blood samples were collected from 15299 “healthy” unrelated subjects of dominantly ethnic Hakka in the Meizhou region, on which hemoglobin electrophoresis and routine blood tests were performed. Suspected cases with hemoglobin variants and hereditary persistence of fetal hemoglobin (HPFH) were further characterized by PCR, DNA sequencing, reverse dot blot (RDB) or multiplex ligation-dependent probe amplification (MLPA). In addition, 1743 samples were randomly selected from the 15299 subjects for thalassemia screening, and suspected thalassemia carriers were identified by PCR and RDB.ResultsThe gene frequency of hemoglobin variants was 0.477% (73/15299). The five main subgroups of the ten hemoglobin variants were Hb E, Hb G-Chinese, Hb Q-Tahiland, Hb New York and Hb J-Bangkok. 277 cases (15.89%, 277/1743) of suspected thalassemia carriers with microcytosis (MCV<82 fl) were found by thalassemia screening, and were tested by a RDB gene chip to reveal a total of 196 mutant chromosomes: including 124 α-thalassemia mutant chromosomes and 72 β-thalassemia mutant chromosomes. These results give a heterozygote frequency of 11.24% for common α and β thalassemia in the Hakka population in the Meizhou region. 3 cases of HPFH/δβ-thalassemia were found, including 2 cases of Vietnamese HPFH (FPFH-7) and a rare Belgian Gγ(Aγδβ)0–thalassemia identified in Chinese.ConclusionsOur results provide a detailed prevalence and molecular characterization of hemoglobinopathies in Hakka people of the Meizhou region. The estimated numbers of pregnancies each year in the Meizhou region, in which the fetus would be at risk for β thalassemia major or intermedia, Bart’s hydrops fetalis, and Hb H disease, are 25 (95% CI, 15 to 38), 40 (95% CI, 26 to 57), and 15 (95% CI, 8 to 23), respectively.
Highlights
Hemoglobinopathy is a kind of genetic defects that result in abnormal structure of one of the globins [1] and, in most cases, is inherited as autosomal co-dominant traits [2]
The five main subgroups of the ten hemoglobin variants were hemoglobin E (Hb E), Hb G-Chinese, Hb Q-Tahiland, Hb New York and Hb J-Bangkok. 277 cases (15.89%, 277/ 1743) of suspected thalassemia carriers with microcytosis (MCV,82 fl) were found by thalassemia screening, and were tested by a reverse dot blot (RDB) gene chip to reveal a total of 196 mutant chromosomes: including 124 a-thalassemia mutant chromosomes and 72 b-thalassemia mutant chromosomes
These results give a heterozygote frequency of 11.24% for common a and b thalassemia in the Hakka population in the Meizhou region. 3 cases of hereditary persistence of fetal hemoglobin (HPFH)/db-thalassemia were found, including 2 cases of Vietnamese HPFH (FPFH-7) and a rare Belgian Gc(Acdb)0–thalassemia identified in Chinese
Summary
Hemoglobinopathy is a kind of genetic defects that result in abnormal structure of one of the globins [1] and, in most cases, is inherited as autosomal co-dominant traits [2]. The hemoglobinopathies encompass all genetic diseases of hemoglobin. They fall into two main groups: thalassemia syndromes and structural hemoglobin variants (abnormal hemoglobins) [1,3]. A few hemoglobin variants show the hematological phenotype of thalassemia, such as abnormal hemoglobin E (Hb E) [4] Another heterogeneous group of related Hb disorders, hereditary persistence of fetal hemoglobin (HPFH), is usually caused by mutations in the b-globin gene cluster, lead to reduced expression of certain types of globin genes and is usually classified into ‘the thalassemia syndromes’. Hemoglobinopathies are the most common inherited diseases in southern China. There have been only a few epidemiological studies of hemoglobinopathies in Guangdong province
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