A recent study found that strict adherence to High-Throughput Sequencing (HTS) technology based carrier screening in pre-conceptional or early pregnancy stage, along with complete follow-up and retesting, can achieve high efficiency in prevention of severe thalassemia birth defects.
The study is led by scientists from BGI Genomics, the First People's Hospital of Yunnan Province, the Affiliated Chenzhou Hospital of Hengyang Medical School of University of South China and collaborative institutes. The results have been published in the Journal of Genetics and Genomics early this month.
Journal of Genetics and Genomics (JGG) is an international academic journal that publishes peer-reviewed original research articles, covering cutting-edge discoveries and significant advancements in the fields of genetics and genomics.
Efficiency of HTS in Thalassemia Screening
Severe thalassemia includes conditions like Hb Bart's hydrops fetalis and transfusion-dependent thalassemia (TDT), which includes β-thalassemia major and two non-deletional Hemoglobin H diseases.
The team conducted HTS-based genetic screening on 28,043 women of childbearing age. They then evaluated the effectiveness of the screening by following the pregnancy outcomes of the participants for at least one year. The study found that HTS technology enables accurate identification of rare variants of α/β thalassemia. Its screening efficiency was significantly higher than traditional methods.
Among the 25,053 live births over six months old, only two children were born with severe thalassemia. These cases resulted from issues in the screening process. In both cases, the mothers had rare variants of thalassemia and refused to undergo prenatal diagnosis, which led to the birth of severe thalassemia infants. No severe cases occurred among live births that strictly adhered to the screening protocol.
The study revealed that 15.07% of women were carriers of thalassemia. These women were categorized based on their spouses' screening results into high-risk (0.75%), low-risk (25.86%), and unknown-risk (69.19%) groups. Prenatal diagnosis confirmed 59 fetuses with severe thalassemia, all of which were in high-risk couples.
Genetic Diversity of Thalassemia
The study identified 64 rare thalassemia variants in 287 individuals, revealing the genetic diversity of the disorder. Furthermore, researchers observed that migrant populations significantly impacted carrier rates. A staggering 93.90% of migrants to Chenzhou originated from high-prevalence regions in southern China.
"HTS offers a reliable way to detect thalassemia carriers. By strictly adhering to the protocol of pre-conceptional and early pregnancy thalassemia screening, the occurrence of severe thalassemia birth defects can be effectively prevented," said Dr. Peng Zhiyu, Vice President of BGI Genomics, corresponding author of the research. "Our findings highlight the importance of screening and follow-up for high-risk couples. This is especially crucial in areas with high or under-recognized prevalence of thalassemia, where such measures can significantly reduce the disease burden."
This real-world cohort study underscores the critical role of HTS technology in the early detection and prevention of severe thalassemia. It offers a powerful tool to lessen the impact of severe thalassemia in affected populations. This study has laid the foundation for a comprehensive prevention and control plan for the 350 million thalassemia gene carriers worldwide, marking a new era in genetic testing-driven thalassemia prevention and control.
About BGI Genomics
BGI Genomics, headquartered in Shenzhen, China, is the world's leading integrated solutions provider of precision medicine. Our services cover more than 100 countries and regions, involving more than 2,300 medical institutions. In July 2017, as a subsidiary of BGI Group, BGI Genomics (300676.SZ) was officially listed on the Shenzhen Stock Exchange.
