How should pathogenic variants, likely pathogenic variants, and variants of uncertain significance be interpreted, and how should VUS results guide care?

How should pathogenic variants, likely pathogenic variants, and variants of uncertain significance be interpreted, and how should VUS results guide care?

• A. Pathogenic variants are clearly disease-causing; likely pathogenic variants have strong but not definitive evidence; VUS have insufficient evidence and should not drive management changes—clinical decisions rely on established pathogenic/likely pathogenic findings and family segregation data.
• B. Pathogenic variants are never disease-causing; likely pathogenic variants are always disease-causing; VUS have no clinical relevance.
• C. VUS results should drive major risk-reducing surgeries.
• D. All variant results are treated identically in clinical decisions.

Answer: (A)

Interpreting variant classifications and guiding care revolves around matching the strength of evidence to clinical action. Pathogenic variants are established disease-causing changes, with strong evidence that they increase risk or cause disease. Likely pathogenic variants have substantial, but not definitive, evidence pointing to pathogenicity; they are treated as high risk in many situations, especially when corroborated by family history or segregation data. Variants of uncertain significance have insufficient or conflicting evidence to determine if they influence disease risk, so they should not be used to justify major changes in management. Instead, decisions should rely on established pathogenic or likely pathogenic findings and on how the variant segregates with disease in families when that information is available. This is why major risk-reducing actions or drastic interventions are not prompted by a VUS. VUS results call for cautious counseling, possible periodic reanalysis as new data accumulate, and consideration of standard risk factors and family history. If a variant is classified as pathogenic or likely pathogenic, then management decisions—such as enhanced surveillance, risk-reducing strategies, or targeted therapies—are guided by that classification and by additional supporting data like segregation in relatives. The other ways of treating all variant results the same or allowing VUS to drive major interventions aren’t appropriate because they would apply actions without solid evidence of risk, which could expose patients to unnecessary procedures or misses in appropriate care.

Interpreting variant classifications and guiding care revolves around matching the strength of evidence to clinical action. Pathogenic variants are established disease-causing changes, with strong evidence that they increase risk or cause disease. Likely pathogenic variants have substantial, but not definitive, evidence pointing to pathogenicity; they are treated as high risk in many situations, especially when corroborated by family history or segregation data. Variants of uncertain significance have insufficient or conflicting evidence to determine if they influence disease risk, so they should not be used to justify major changes in management. Instead, decisions should rely on established pathogenic or likely pathogenic findings and on how the variant segregates with disease in families when that information is available.

This is why major risk-reducing actions or drastic interventions are not prompted by a VUS. VUS results call for cautious counseling, possible periodic reanalysis as new data accumulate, and consideration of standard risk factors and family history. If a variant is classified as pathogenic or likely pathogenic, then management decisions—such as enhanced surveillance, risk-reducing strategies, or targeted therapies—are guided by that classification and by additional supporting data like segregation in relatives.

The other ways of treating all variant results the same or allowing VUS to drive major interventions aren’t appropriate because they would apply actions without solid evidence of risk, which could expose patients to unnecessary procedures or misses in appropriate care.