Educational Content: This article is for informational purposes only and does not constitute medical advice. Always consult a healthcare provider for diagnosis and treatment.
Definition of Penetrant trait
Medically reviewed by Min Clinic Staff | Updated: January 2026
Penetrant trait: A genetic trait (characteristic) that is present in the genome and manifests itself in the individual. By contrast, a nonpenetrant trait is one that, although present, does not manifest itself.
If, for example, 100 people have a particular genetic trait but only 80 of them express it, the penetrance of that trait is 80%. The trait is penetrant and expresses itself in 80% of people who have it.