Abstract
The incidence of haemoglobinopathy is high in China, especially south of the Yangtze River. However, the exact status of haemoglobinopathy in Sichuan is unknown. To carry out a detailed research of haemoglobinopathy in individuals living in Sichuan, 13,298 subjects without clinical symptoms who were living in Sichuan Province, with an age distribution of 5-73 years, were included in this study. Between March 2014 and July 2017, these subjects received examinations at the Medical Lab of Chengdu Women's & Children's Central Hospital. Mean corpuscular volume (MCV) < 82 fL or mean corpuscular haemoglobin (MCH) < 27 pg was used to indicate haemoglobinopathy carriers. Abnormal haemoglobin was screened by electrophoresis, and genes were sequenced to identify genotypes. Genotype diagnosis of alpha- and beta-thalassaemia was carried out by using PCR and shunt hybridization. There were 638 suspected haemoglobinopathy carriers (4.80%, 638/13,298). DNA sequencing identified 6 subjects with abnormal haemoglobin genotypes and 15 subjects with Hb E. The frequency of heterozygosity for thalassaemia was 4.12% (1.48% for α-thalassaemia and 2.61% for β-thalassaemia) in Sichuan Province. The mutation spectrum of α-thalassaemia consisted of the five most common mutations: --(SEA), -α(3.7), -α(4.2), α(CS), and α(QS). Seven types of β-thalassaemia mutation were found in this study: CD41-42 (-TTCT) was the most frequent (28.47%), followed by 17 (A > T), -28 (A > G), and IVS-II-654 (C > T). The main abnormal haemoglobin genotype (HbE) and thalassaemia genotype (--(SEA), CD41-42 (-TTCT)) were consistent with those in other regions of China, but the carrier rate of β-thalassaemia in Sichuan was higher than that of α-thalassaemia.