7/27/2019 Interpreting Genetic Tests Tool

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Results Interpretation & Application ToolkitInterpretation of results 

Published October 2013© NCHPEG All rights reserved 

Key Points when Interpreting Genetic Testing Results:

  The interpretation of a genetic result depends on the context of the individual and family.

  If a patient meets clinical criteria for a genetic syndrome based on his or her medical and family history, the patient should

be screened and managed according to guidelines for the syndrome, even in the absence of confirmatory genetic testing.

  When testing an unaffected relative, negative or VUS results are not fully informative unless a mutation has already been

identified in the family.

  Genetic test results are not always straightforward. Be cautious with counseling and management changes when results are

uninformative or VUS. In these cases, consider communicating with the lab or a genetics professional.

Possible Outcomes of Genetic Testing Table for Child Neurologists

Clinical Presentation

of Person to be Tested

Genetic Testing Result Interpretation Recommendations for Family Members

Affected or

symptomatic

Positive

(One dominant or two

recessive mutations

identified)

True positive. Disease-

causing mutation

identified. Test confirms

clinical diagnosis.

Mutation-specific testing of first-degree

family members is strongly

recommended. Those with positive

results are at risk for developing the

disease.

Affected or

symptomatic

Negative

(No dominant mutations

found, one or no recessive

mutations identified)

Genetic testing does not

rule out the diagnosis or a

genetic cause of the

disease.

Testing of family members not indicated.

However, clinical follow-up testing is

recommended.

Affected or

symptomatic

Variant of unknown clinical

significance

Genetic testing at this time

is uninformative.

If symptomatic family members are

found to have the same variant, it is

more likely that the variant is disease

causing. If family members who do not

have symptoms have the same variant, it

could be benign.

Unaffected or

asymptomatic

Positive Patient is at risk for

developing the disease.

Testing of family members is

recommended. Those with negative

results are not at an increased risk for

the disease.

Unaffected or

asymptomatic

Negative Patient is likely not at

increased risk for the

disease.

Testing of family members is not

indicated.

Unaffected or

asymptomatic

Variant of unknown clinical

significance

Genetic testing at this time

in uninformative.

If symptomatic family members are

found to have the same variant, it is

more likely that the variant is diseasecausing. If family members who do not

have symptoms have the same variant, it

could be benign.