Hi, this is Tom, and in this episode I'm going to be going through genetic testing.

And you can find notes at 0.0.2finals.com and in the 0 to Finals Pediatrics book,

and you can find flashcards and questions at members.0.0 tofinals.com.

So let's jump straight in. When it comes to genetic testing, there are different types of genetic testing, such as diagnostic testing, predictive testing,

carrier testing, somatic testing, prenatal testing, and so on. Diagnostic testing involves testing for a specific genetic condition to make a diagnosis.

Examples include testing for CFTR gene mutations for cystic fibrosis, or for trisomy 21, or three copies of chromosome 21, for Down syndrome.

Predictive testing involves testing a person for a specific gene mutation that may have

implications for them in the future. For example, testing the BRCA1 or BRCA1 gene mutation, which increases

the risk of developing breast cancer. Another example is testing pre-symptomatic patients or people

without any symptoms for the CAG repeat expansion in the HTT gene,

which will lead to Huntington's disease.

Carrier testing involves testing asymptomatic individuals for a genetic mutation

associated with a specific autosomal recessive or ex-linked recessive

disorder to estimate the risk of them passing it on to their children.

An example is testing for the cystic fibrosis gene mutation when other family members are affected.

Somatic testing involves analysing tumour cells in patients with cancer to identify mutations.

This usually involves next generation sequencing or NGS panels that test for many genes inside the tumor cells.

An example of where tumor testing is used is to identify the HER2 gene amplification on breast

cancer cells, which indicates a role for targeted therapies treating the breast cancer which are specific to this her two gene,

such as Trastazumab.

Other scenarios where genetic testing may be used include prenatal testing, which is testing for genetic

conditions in the fetus during pregnancy,al testing, which is testing for genetic conditions in the fetus during pregnancy.

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