Effects of a genetic variant
View image on Flickr or Pinterest
The same genetic variant can cause different effects from person to person. This can be due to either the penetrance or expressivity of the variant.
Penetrance
Sometimes, everyone who inherits a particular disease-causing variant will develop the disease it is associated with – this is known as a condition with complete penetrance. Other conditions have reduced penetrance – meaning that not everyone who inherits them will go on to develop disease. The reasons for this are unclear, but are likely a combination of genetic and environmental factors. It’s not currently possible to predict who will develop a disease with reduced penetrance and who will not.
Expressivity
The signs and symptoms of a genetic condition can vary from person to person – this is known as variable expressivity. Some people with a genetic variant may only have mild symptoms, while others with a variant in the same gene develop life threatening complications. The reasons for variable expressivity are also unclear, but are probably a combination of genetic and environmental factors.
Tags: image, variant, genetic disease
Thoughts about DNA Base? Take a few seconds to fill in our survey and let us know your feedback.