Does Digeorge syndrome impact B cells?

[Qester]

As the title says,

Does having a lack of a thymus and thus a decrease in T lymphocytes have a significant impact on B cells? I would assume since the B and T cells can't interact B cells can't undergo isotype switching and thus would either present as Hyper-IgM or low levels of Ig but I haven't seen anything on this.

If not, why are B cell intact?

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[Transposony]

DiGeorge syndrome is most commonly due to thymic hypoplasia and, therefore, there are enough T cells present for class switching etc.
It can present as a variable spectrum of disorders depending on the degree of T cell deficiency and a complete absence of thymus and T-cells will present with SCID phenotype.
The classic DiGeorge syndrome is HY for Step 1.
Another HY point being that DiGeorge syndrome is a genetic risk factor for schizophrenia.

 

[worldbeater]

Other HY facts:
-Affects Chromosome 22
-3 and 4th pharyngeal pouch affected

 

[Qester]

DiGeorge syndrome is most commonly due to thymic hypoplasia and, therefore, there are enough T cells present for class switching etc.
It can present as a variable spectrum of disorders depending on the degree of T cell deficiency and a complete absence of thymus and T-cells will present with SCID phenotype.
The classic DiGeorge syndrome is HY for Step 1.
Another HY point being that DiGeorge syndrome is a genetic risk factor for schizophrenia.

Perfect, exact explanation I was hoping for, thank you

 

[worldbeater]

-3 and 4th pharyngeal pouch affected

Also another point, pouches are where glands are made, where as arches are where bone and tissue are created.

That's why you have a glandular problem in this condition.

 

[SKaminski]

holy ****, ya'll are dropping all kinds of knowledge bombs

 

[Phloston]

As transposony has said the phenotypes vary. On the Usmle they want you to know it's T cell. If they mention infections with bacteria, viruses, protozoa, etc., they're referring to B and T cells and the answer is SCID. Just obviously be on the lookout for other relevant information in the vignette that might support DDx and use your best judgment.