Genetic Heterogeneity of the β-Globin Gene in Various Geographic Populations of Yunnan in Southwestern China

Abstract

ObjectivesThe aim of this study was to investigate the geographic distribution of β-globin gene mutations in different ethnic groups in Yunnan province.MethodsFrom 2004 to 2014, 1,441 subjects with hemoglobin disorders, identified by PCR-reverse dot blot and DNA sequencing, were studied according to ethnicity and geographic origin. Haplotypes were examined among 41 unrelated thalassemia chromosomes.ResultsEighteen β-thalassemia mutations and seven hemoglobin variants were identified for 1,616 alleles in 22 different ethnic groups from all 16 prefecture-level divisions of Yunnan. The prevalence of β-thalassemia was heterogeneous and regionally specific. CD 41-42 (-TCTT) was the most prevalent mutation in the populations of northeastern Yunnan. CD 17 (A>T) was the most common mutation in the populations of southeastern Yunnan, especially for the Zhuang minority, whereas Hb E (CD 26, G>A) was the most prevalent mutation in populations of southwestern Yunnan, especially for the Dai minority. Among the seven types of haplotypes identified, CD 17 (A>T) was mainly linked to haplotype VII (+ - - - - - +) and IVS-II-654 (C>T) was only linked to haplotype I (+ - - - - + +).ConclusionOur data underline the heterogeneity of β-globin gene mutations in Yunnan. This distribution of β-globin mutations in the geographic regions and ethnic populations provided a detailed ethnic basis and evolutionary view of humans in southern China, which will be beneficial for genetic counseling and prevention strategies.

Molecular Heterogeneity of Thalassemia among Pregnant Laotian Women

“…In addition to Hb E, the β-globin mutations reported in this study, i.e. CD 17 (A-T), CD 41/42 (-TTCT), and nucleotide -28 (A-G), were also similar to those reported in neighboring countries [5,[19][20][21] . Interaction of these abnormal genes can lead to several complex thalassemia syndromes, reflecting the serious health burden within the country.…”

Gene frequency and haplotype distribution of hemoglobin E among seven minority groups of Yunnan, China

“…Recent hospital-based studies on individuals undergoing a premarital health check or prenatal examination reported that HbE was the most prevalent mutation of HBB gene in populations from southwestern Yunnan, especially in minority groups such as Chinese Thai (Dai), Jingpo, and Achang (He et al, 2016;Zhang et al, 2015). In this study, a total of 1488 individuals from seven minority groups from Yunnan province were studied.…”

“…To accurately reconstruct haplotypes associated with b E -and b A -globin genes, individuals with other common beta thalassemia mutations in Yunnan including CD17, CD41-42, and IVS-II-654 (Zhang et al, 2015), and individuals who were compound heterozygotes for HbE/b-thalassemia, were excluded from the haplotype analysis. After excluding subjects with missing genotypes for any restriction site, the haplotypes of the seven polymorphic sites for both the b E and b A bearing chromosomes were identified using the population genetics data analysis package Arlequin V3.5.2 (Excoffier and Lischer, 2010).…”

“…In spite of the fact that there are very close population and geographic relationships between Yunnan and the HbE-prevalent countries of Southeast Asia, little is known about the distribution and evolution of HbE in Yunnan ethnic populations. A large-scale survey conducted in the 1980s indicated that Yunnan had the highest prevalence of abnormal hemoglobin and HbE in China (Zeng and Huang, 1987), and a recent hospital-based study showed that HbE is the dominant mutation in b thalassemia patients with different ethnic backgrounds in Yunnan (Zhang et al, 2015). However, few data on the frequencies and origins of HbE in minority groups in Yunnan are available.…”

Analysis of deletional hereditary persistence of fetal hemoglobin/δβ‐thalassemia and δ‐globin gene mutations in Southerwestern China

“…Although δ‐thalassemia has no clinical significance, the disrupted function of δ‐globin may lead to aberrant measurements of Hb A 2 , and may complicate the diagnosis of β‐thalassemia when relying on the Hb A 2 measurements of the patient (Amirian et al, ). β‐Thalassemia is highly prevalent in Yunnan, China, and has a high genetic heterogeneity (Zhang et al, ). Identification of the clinical and hematological phenotypes of these causative mutations and their relative frequency in the population can improve our understanding of broader patterns across human populations.…”