Immunodeficiency diseases arise when individuals lack one or more components of their immune system, and are identified by an individual's history of persistent or recurrent infections. Some genetic defects (mutations or small deletions) can cause profound defects in an immune cell population; alternatively, in some cases, such small defects occur that there is no visible effect on immune responses. The diagram in Figure shows simplified versions of the immunoglobulin heavy chain locus, the T-cell receptor $\beta$chain locus, and the locus encoding the RAG-1 and RAG-2 recombinases. For the sake of this question, imagine that these diagrams represent all of the gene segments present in the immunoglobulin heavy chain and T-cell receptor $\beta$ chain locus.
You now analyze five individuals, each of which has a single inactivating mutation in a region of one of these three loci. These mutations are each indicated by a red 'X' in Figure , and are numbered 1-5. For each of these inactivating mutations, indicate the alterations and/or defects that would be seen in the repertoire of antigen receptors found in mature B and T cells in that individual. Also, for each mutation, indicate whether the individual would likely show any immunodeficiency, such as a history of recurrent infections.

Question

Immunodeficiency diseases arise when individuals lack one or more components of their immune system, and are identified by an individual's history of persistent or recurrent infections. Some genetic defects (mutations or small deletions) can cause profound defects in an immune cell population; alternatively, in some cases, such small defects occur that there is no visible effect on immune responses. The diagram in Figure shows simplified versions of the immunoglobulin heavy chain locus, the T-cell receptor $\beta$chain locus, and the locus encoding the RAG-1 and RAG-2 recombinases. For the sake of this question, imagine that these diagrams represent all of the gene segments present in the immunoglobulin heavy chain and T-cell receptor $\beta$ chain locus.  
You now analyze five individuals, each of which has a single inactivating mutation in a region of one of these three loci. These mutations are each indicated by a red 'X' in Figure , and are numbered 1-5. For each of these inactivating mutations, indicate the alterations and/or defects that would be seen in the repertoire of antigen receptors found in mature B and T cells in that individual. Also, for each mutation, indicate whether the individual would likely show any immunodeficiency, such as a history of recurrent infections.

Quizplus · Accepted Answer

The Answer of Immunodeficiency diseases arise when individuals lack one or more components of their immune system, and are identified by an individual's history of persistent or recurrent infections. Some genetic defects (mutations or small deletions) can cause profound defects in an immune cell population; alternatively, in some cases, such small defects occur that there is no visible effect on immune responses. The diagram in Figure shows simplified versions of the immunoglobulin heavy chain locus, the T-cell receptor $\beta$chain locus, and the locus encoding the RAG-1 and RAG-2 recombinases. For the sake of this question, imagine that these diagrams represent all of the gene segments present in the immunoglobulin heavy chain and T-cell receptor $\beta$ chain locus.  
You now analyze five individuals, each of which has a single inactivating mutation in a region of one of these three loci. These mutations are each indicated by a red 'X' in Figure , and are numbered 1-5. For each of these inactivating mutations, indicate the alterations and/or defects that would be seen in the repertoire of antigen receptors found in mature B and T cells in that individual. Also, for each mutation, indicate whether the individual would likely show any immunodeficiency, such as a history of recurrent infections.

Immunodeficiency Diseases Arise When Individuals Lack One or More Components β\betaβ

Immunodeficiency Diseases Arise When Individuals Lack One or More Components $\beta$