Which of the examples of genetic testing below are prognostic tests? Which are diagnostic?
An adult diagnosed with Asperger syndrome (AS) has a genetic test that reveals an SNP in the GABRB3 gene that is significantly more common in people with AS than the general population.

Verified step by step guidance

1. Understand the difference between diagnostic and prognostic tests: Diagnostic tests are used to confirm or rule out a specific genetic condition in an individual who is showing symptoms. Prognostic tests, on the other hand, provide information about the likely course or outcome of a condition, often predicting the severity or progression of a disease.
2. Analyze the scenario: The individual has already been diagnosed with Asperger syndrome (AS). The genetic test is being used to identify a SNP (single nucleotide polymorphism) in the GABRB3 gene that is more common in people with AS than in the general population.
3. Determine the purpose of the test: Since the individual is already diagnosed with AS, the test is not being used to confirm the diagnosis. Instead, it is identifying a genetic variant associated with the condition, which could provide information about the genetic basis or potential progression of AS.
4. Classify the test: Based on the purpose, this test is more aligned with a prognostic test because it provides additional information about the genetic factors associated with AS rather than diagnosing the condition itself.
5. Conclude: The genetic test in this scenario is a prognostic test, as it is not used to diagnose AS but rather to explore genetic associations that may have implications for understanding the condition's progression or characteristics.

Key Concepts

Prognostic vs. Diagnostic Testing

Prognostic tests are used to predict the likelihood of developing a disease or the likely course of an existing disease, while diagnostic tests are used to confirm or rule out a specific condition. Understanding the distinction is crucial for interpreting genetic test results, as it informs whether the test is assessing risk or confirming a diagnosis.

Single Nucleotide Polymorphism (SNP)

A Single Nucleotide Polymorphism (SNP) is a variation at a single position in a DNA sequence among individuals. SNPs can influence how individuals respond to diseases, medications, and environmental factors, making them significant in genetic testing for both diagnostic and prognostic purposes.

GABRB3 Gene and Asperger Syndrome

The GABRB3 gene encodes a subunit of the GABA receptor, which is involved in inhibitory neurotransmission in the brain. Variations in this gene have been associated with neurodevelopmental disorders, including Asperger syndrome, highlighting the importance of genetic testing in understanding the genetic basis of such conditions.