Rh Blood Group History and Genetics

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Questions and Answers

Who first discovered the antibody suspected to cause hemolytic disease of the fetus and newborn?

Levine and Stetson (correct)

Landsteiner and Wiener

Rhesus monkeys

Guinea pigs

What does the absence of the D antigen in an individual typically indicate?

A mutated RHD allele

The individual is Rh(D)-negative (correct)

The presence of a D antigen

The individual is Rh(D)-positive

What is the primary role of the RHD gene?

Encodes for the anti-LW antibody

Regulates blood type variability

Codes for the D antigen (correct)

Codes for the C and E antigens

How many times do the RhD and RhCE proteins pass through the red blood cell membrane?

A dozen times Signup and view all the answers

What is a distinguishing feature of Rh proteins compared to ABO or MNS blood group antigens?

They are nonglycosylated Signup and view all the answers

Which of the following alleles is not part of the RHCE gene?

RhD Signup and view all the answers

What happens when the RHD gene is deleted in an individual?

The individual is usually Rh(D)-negative Signup and view all the answers

What is the significance of the amino acid differences in C and c proteins as well as E and e proteins?

They allow the body to recognize them as foreign antigens Signup and view all the answers

What role does RhAG play in relation to Rh expression?

It regulates the expression of Rh antigens. Signup and view all the answers

Which genotype contributes to the amorphic-type Rhnull phenotype?

Deletion of the RHD gene. Signup and view all the answers

How did the Rh system nomenclature proposed by Rosenfield categorize antigens?

In order of their historical discovery. Signup and view all the answers

In the Fisher-Race terminology, what does the presence of a minus sign in front of the number indicate?

An individual tested negative for that antigen. Signup and view all the answers

What did Tippett's postulation about Rh genetic expression primarily contribute to our understanding?

It confirmed and expanded the concept of two closely linked genes. Signup and view all the answers

Which of the following statements accurately reflects the Wiener haplotypes theory?

A single gene at a single locus produces multiple antigens. Signup and view all the answers

What condition results from individuals lacking all Rh antigens?

Hemolytic anemia related to Rhnull phenotype. Signup and view all the answers

What did early theories of Rh inheritance incorrectly propose about the inheritance of Rh antigens?

That they are inherited without a chance for crossing over. Signup and view all the answers

Study Notes

History of Rh

In 1939, Levine and Stretson identified a factor causing hemolytic disease of the fetus and newborn (HDFN).
The factor was later identified as the D antigen.
In 1941, Landsteiner and Wiener discovered an antibody created by rabbits and guinea pigs reacting with 85% of human red blood cells.
Initially thought to be anti-D, this antibody was later identified as anti-LW.

The RHD and RHCE Genes and Proteins

RHD and RHCE genes are located on chromosome 1.
RHD gene codes for the D antigen, indicating Rh-positive.
The absence of the D antigen, indicating Rh-negative, is indicated by the absence of the gene.
RHCE gene codes for RhCE protein carrying C/c and E/e antigens.
The C and c proteins and E and e proteins differ by just a few amino acids.
Rh proteins are not glycosylated and have structural and ion channel roles.

Rh-Associated Glycoprotein (RhAG)

RhAG is encoded by the RHAG gene on chromosome 6.
It's required for proper Rh expression.
Individuals lacking all Rh antigens (Rhnull phenotype) suffer from hemolytic anemia.
Amorphic-type Rhnull results from the deletion of the RHD gene and mutation of the RHCE gene.
Regulator-type Rhnull results from mutations in the RHAG gene.
Relatives of regulator-type Rhnull can express a milder form of Rh antigen suppression known as Rhmod.

Rh System Nomenclature

Tippett proposed that Rh genetic expression is controlled by two linked genes.
This theory was later confirmed by molecular analysis and identification of RHD and RHCE.
Fisher and Race suggested three sets of alleles within the Rh system, linked closely enough to be inherited as a single unit.
In 1962, Rosenfield proposed a numerical model for Rh blood group antigens using numbers in order of discovery.
A minus sign indicates negative results, while the absence of a minus sign indicates positive results.
Wiener postulated that Rh antigens are inherited as a product of a single gene at a single locus.
This single gene coded for an agglutinogen made up of multiple antigens.

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Description

Explore the historical discoveries related to the Rh blood group system, including key findings by Levine, Stretson, Landsteiner, and Wiener. Delve into the genetics of the RHD and RHCE genes, their roles, and the importance of RhAG in blood group expression.