Before knowing the new MAL Blood Group, we want to discuss the history of blood group systems. Earlier in1900s, it was believed that all types of blood were similar, but it was believed misunderstanding that caused fatal blood transfusion in humans. Later, in several discoveries, it was confirmed that different surface markers were found on red blood cells, representing their blood groups.
Later it was found that these surface markers provide an immune response, so it’s called an antigen. The membrane of each blood cell contains millions of antigens their immune system prevents those. But, when patients receive a blood transfusion, their immune system recognizes antigens, if it’s different from their own then causes clumping of red blood cells, and finally, the patient dies.
Based on the clumping of red blood cells Karl Landsteiner discovered the first human blood groups (ABO) in 1901, gradually from 1927, other blood groups were also discovered. After discovering the blood group systems, the blood transfusion becomes safe. For this discovery, he got the Nobel Prize in 1930. In the ABO blood group, four antigens are found as represented in the following table. The ABO locus has three main alleles forms: A, B, and O. The A allele encodes a glycosyltransferase that produces the A antigen (N-acetylgalactosamine is its immunodominant sugar), and the B allele encodes a glycosyltransferase that creates the B antigen (D-galactose is its immunodominant sugar). The most important function of this blood group is in transfusion reactions and identifying hemolytic diseases in newborns.
Known Blood Group Systems
Recently, a groundbreaking discovery of a new MAL blood group was made by scientists from NHSBT-Bristol, ending a decades-long puzzle. Including the new MAL blood group, now 47 blood group systems have been discovered. Blood groups are antigens and these are genetically determined by 50 genes. It is a groundbreaking discovery that has unveiled a new blood group system, MAL, ending a decades-long puzzle. This discovery has solved the problems faced by AnWj negative patients. Now scientists have developed genetic tests to identify patients missing the AnWj antigen. A few Important blood group systems are depicted in the following image.
Key findings of the new MAL blood group
The discovery of a new MAL blood group system helps researchers/doctors perform genotyping tests to lower blood transfusion-related problems in AnWj-negative patients.
AnWj Antigen: The researchers discovered the genetic basis for the AnWj antigen, allowing for a better understanding and treatment of uncommon patients who lack this blood group.
MAL Blood Group System: The discovery confirms MAL as the 47th blood group system containing the AnWj antigen.
Genetic Cause: Researchers discovered homozygous deletions in the MAL gene linked to the hereditary AnWj-negative phenotype.
Transfusion Safety: The study enables the creation of new genotyping tests to discover rare AnWj-negative patients, thereby lowering transfusion-related problems.
The most prevalent
explanation for being AnWj negative is that patients have a hematological
disease that suppresses antigen expression.
Only a small percentage of persons are AnWj-negative due to a hereditary factor. The study included five genetically AnWj-negative individuals, including an Arab-Israeli household. The blood test included the sample donated by a women in 2015 who was the first AnWj-negative person discovered in the 1970s.
The researchers employed whole exome sequencing, which is the genetic sequencing of all DNA that encodes proteins, to demonstrate that these uncommon inherited cases were caused by homozygous DNA sequence deletions in the MAL gene, which codes for the Mal protein.
Relevancy of this discovery:
With this new knowledge, healthcare experts can enhance the detection and management of patients who may be lacking this blood group, representing a significant advancement in the field of transfusion hematology.