Penetrance

Penetrance is a term used in genetics describing the proportion of individuals carrying a particular variation of a gene (the genotype) that also express a particular trait (the phenotype). For example, Huntingtons disease has 95% penetrance, whereby 5% of those with the dominant allele for Huntingtons don't acquire the disease and 95% do. Penetrance is the percentage of individuals with a specific genotype which possess an associated phenotype. For example, if 50% of the individuals carrying the "blue" gene are blue, the "blue" gene has 50% penetrance. Penetrance only considers whether individuals express the trait or not — for variation in the degree of expression of a given trait, see expressivity.
See more at Wikipedia.org...

(n.)
Alt. of Penetrancy
  

The likelihood a given gene will result in disease. For example, if half (50%) of the people with the neurofibromatosis (NF) gene have the disease NF, the penetrance of the NF gene is 0.5.

The proportion of individuals with a given genotype (heterozygotes for a dominant gene) who express an expected trait, even if mildly. If a disease gene is not causing the disease in all its carriers, its penetrance is low [not to be mixed with variable expession]
BRCA1 mutations show both age-dependent penetrance and overall reduced penetrance, the life-time risk for a female mutation carrier
being estimated at around 70%. Breast cancer is also an example of an autosomal condition where penetrance is sex-dependent. While male mutation carriers can develop breast cancer (particularly with BRCA2 mutations), females are at much greater risk.

انتفاذ ( نفذ