Which of the examples of genetic testing below are prognostic tests? Which are diagnostic?
Genetic testing in a healthy teenager identifies an SNP correlated with autism.

Verified step by step guidance

1. Understand the difference between prognostic and diagnostic tests: Prognostic tests predict the likelihood of developing a condition in the future, while diagnostic tests confirm the presence of a condition in an individual who is already showing symptoms.
2. Analyze the scenario: The genetic testing identifies a single nucleotide polymorphism (SNP) correlated with autism in a healthy teenager. This means the teenager does not currently exhibit symptoms of autism.
3. Determine the type of test: Since the teenager is healthy and the test is identifying a genetic marker associated with a potential future condition, this test is considered prognostic rather than diagnostic.
4. Consider the implications: Prognostic tests like this one provide information about genetic predisposition but do not confirm the presence of the condition itself.
5. Conclude the classification: Based on the analysis, the genetic testing described in the problem is a prognostic test, not a diagnostic test.

Key Concepts

Prognostic Testing

Prognostic testing assesses the likelihood of developing a disease or condition in the future based on genetic markers. These tests help predict the risk of disease onset, allowing for early intervention or monitoring. For example, identifying a single nucleotide polymorphism (SNP) associated with autism in a healthy individual can indicate a potential risk, but it does not confirm the presence of the condition.

Diagnostic Testing

Diagnostic testing is used to confirm or rule out a specific genetic condition in individuals who are symptomatic or at risk. These tests provide definitive information about the presence of a disease, often guiding treatment decisions. Unlike prognostic tests, diagnostic tests focus on identifying existing conditions rather than predicting future risks.

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. In the context of genetic testing, identifying an SNP associated with a condition like autism can provide insights into genetic predispositions, but it is important to interpret these findings within a broader context of genetic and environmental interactions.