Hi, this is Tom, and in this episode I'm going to be going through T-cell disorders,

and you can find notes at 0.0.0.5.com and in the 0.0-to-finals pediatrics book,

and you can find flashcards and questions at members.0-0-0.com. So let's jump straight in. T-lymaphysites or T-cells are an essential

component of the immune system. They help identify and eliminate pathogens and abnormal cells,

for example, cancerous cells. T-cell disorders increase the susceptibility

to viral, fungal and opportunistic infections. Let's start by talking about DeGeorge

syndrome. DeGeorge syndrome also called 22-Q11.2 deletion syndrome, features a micro-deletion in a portion of chromosome 22 that leads to a defect involving the third and fourth pharyngeal pouches.

One of the consequences of this is incomplete development of the thymus gland.

This can result in reduced or absent T-cell production, as the thymus gland plays an essential

role in T-cell production.

Features of DeGeorge syndrome can be remembered with the Catch-22 pneumonic.

C for congenital heart disease.

A for abnormal faces with a characteristic facial appearance.

T for thymus gland incompletely developed,

C for cleft palate,

H for hypoparthoridism,

and resulting hypo-calcemia,

or a low-calsim level,

and 22 for the 22nd chromosome being affected.

Let's talk about a different T-cell disorder called

Purine nucleoside phosphorylase deficiency.

Purine nucleoside phosphorylase deficiency is an autosomal recessive condition.

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