BGI VISTA™ Hemoglobin

BGI VISTA™ Hemoglobin

Introduction

Hemoglobinopathies are the most common monogenic hereditary diseases, affecting a large number of people around the world and causing serious consequences1. Hemoglobinopathies have a clear etiology, as well as clear prevention and control methods, and there are many examples of successful prevention and control practices. Cyprus2, Italy3, the UK4, Iran5, Singapore6, Guangxi (China)7 and many other countries and districts have successfully reduced the rate of severe hemoglobinopathies at birth with prevention and control programs. These successes show that the prevention and control of hemoglobinopathies can be achieved in all countries, regardless of their financial status, when proper programs are effectively implemented.

Hemoglobinopathies consist of sickle cell disease (SCD) and thalassemia. Among newborns with hemoglobinopathies, 83% suffered from SCD and 17% suffered from thalassemia8 (other reports record 70% having SCD and 30% thalassemia9). To highlight the importance of preventing and controlling SCD, SCD was recognized as a public health problem by the United Nations General Assembly in 200810. The World Health Organization (WHO) issued a strategy for SCD prevention in the African Region in 201011 and summarized its implementation progress in 202012. To prevent and control thalassemia, a WHO working group started a guideline for the control of hemoglobin disorders in 198913. Thalassemia International Federation (TIF) published ‘Prevention of Thalassaemias and Other Haemoglobin Disorders’, in 200314.

  1. Thalassemia

Thalassemia is an inherited blood disorder, which is caused by changes in the genes that help make hemoglobin.

1.1 The prevalence of Thalassemia

Thalassemia is prevalent in populations in the Mediterranean area, the Middle East, Trans Caucasus, Central Asia, the Indian subcontinent, and the Far East(Fig.1).

Worldwide 56,000 conceptions have a major thalassemia disorder of which approximately 30,000 are affected by b-thalassemia major and 3500 succumb perinatally from the hydrops fetalis syndrome.

1.2 Clinical symptoms of thalassemia

2) Sickle cell disease

Sickle cell anemia is an inherited red blood cell disorder in which there aren’t enough healthy red blood cells to carry oxygen throughout your body.

2.1 The prevalence of SCD

Estimates suggest that 250,000 children are born annually with sickle cell anemia worldwide. In some areas of sub-Saharan Africa, up to 2% of all children are born with the condition. In broad terms, the prevalence of the sickle-cell trait (healthy carriers who have inherited the mutant gene from only one parent) ranges between 10% and 40% across equatorial Africa and decreases to between 1% and 2% on the north African coast and <1% in South Africa.

In low and middle-income countries, 50%–80% of children with SCD die each year9.

2.2 Clinical symptoms of SCD

  • Periods of pain that can last a few hours to a few days.
  • Blood clots.
  • Swelling in hands and feet.
  • Joint pain that resembles arthritis.
  • Chronic neuropathic pain (nerve pain).
  • Life-threatening infections.
  • Anemia (decrease in red blood cells).

3) Vision

The prevention of births with severe hemoglobinopathies is a key factor for the successful prevention and control of hemoglobinopathies worldwide. The rate of affected newborns is less than 0.3 per 10,000 in Cyprus, Spain, Israel, Lebanon, Turkey, Sri Lanka, and Singapore. The prevalence of affected newborns in Greece and Sardinia has been reduced by more than 90%, but the prevalence is still above 1 per 10,000 (table 1).

Table 1: Results of the implementation of prevention and control programs in various countries

a、b Rate of affected newborns = The number of affected newborns / The number of newborns. The number of affected newborns was derived from Table 2. The number of newborns was derived from Our World in Data 117.
c Reduction rate of affected newborns = (a-b) / a × 100%
d Program duration: Derived from Table 2 (including information from WHO, information of public health project from various countries, and information from published papers).

For many years, BGI has been committed to the prevention and control of thalassemia. In 2012, it was the first company to launch a high-throughput sequencing platform-based thalassemia genetic testing service, which was capable of screening for more than 500 thalassemia types in one test. This made the procedure safe and efficient. The rate of missed detections was low, and the service was able to improve the prevention and control of thalassemia effectively.

4) BGI’s total solution for Hemoglobinopathies

4.1 BGl’s Thalassemia Kit

BGl’s Thalassemia solution applies high-throughput sequencing technology to qualitatively detect 7 thalassemia deletion mutations, α-thalassemia non-deletion mutation of HBA1 gene and HBA2 gene, and the β-thalassemia non-deletion mutation of HBB gene for genetic diagnosis of patients and suspected patients with α and/or β thalassemia.

4.2 BGl’s SCD kit

BGl’s Real -time fluorescent PCR kit for detecting Sickle Cell Disease can be used to achieve qualitative detection of two mutations (HbS and HbC) on HBB gene in genomic DNA of human peripheral blood or blood spot samples.

Hemoglobin S and hemoglobin C represents a large proportion (over 90%) of SCD in most countries of the world.

4.3 BGl’s total solution

The best and cost-effective way to control hemoglobinopathies is by screening couples before they get pregnant. if both are carriers of hemoglobinopathies, she has several options.

  • She can become pregnant and have prenatal diagnostic tests to see if the fetus has the disorder.
  • She can choose to use in vitro fertilization (IVF) with donor eggs or sperm to become pregnant. With this option, the embryo can be tested before it is transferred to the uterus.

PGT-M and PGT-SR are used during IVF treatment with the intention to identify embryos that do not have a genetic condition and to help families have healthy children.

For patients with hemoglobinopathies, there are two effective treatment,

1, At present, severe thalassemia and sickle cell disease can be cured by stem cell transplantation (SCT). However, SCT is only possible for a minority of patients with a suitable human leukocyte antigen (HLA)-matched donor and who can afford the costly treatment.

2 Gene therapy, by autologous transplantation of genetically modified hematopoietic stem cells, currently represents a novel therapeutic promise, after many years of extensive preclinical research for the optimization of gene transfer protocols.

5) Scientific collaboration and endorsement

BGI has published numerous articles with serval partners, including hospitals and universities.

In order to raise attention regarding hemoglobinopathies around the world, and hope hemoglobinopathies prevention and control programs can be integrated into national health plans, BGI has released Global prevention and control of hemoglobinopathies this year.

6) Different screening model

BGI’s new technology of thalassemia screening solution based on high-throughput sequencing has been widely verified from scientific research to clinical application.

At present, the new technology has been incorporated into local poverty prevention and control livelihood projects in Ji’an, Jiangxi, Ganzhou, Changsha County, Hunan, Qianxinan, Guizhou, Bama, Guangxi, Qingyuan, Guangdong, and Baoshan, Yunnan, helping to comprehensively improve the prevention and control hemoglobinopathies in many cities and prevent the birth of children with severe thalassemia.

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