penetrance


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Related to penetrance: expressivity, Incomplete penetrance

penetrance

 [pen´ĕ-trans]
the frequency with which a heritable trait is manifested by individuals carrying the principal gene or genes conditioning it.

pen·e·trance

(pen'ĕ-trans),
The frequency, expressed as a fraction or percentage, of people who are phenotypically affected, among those of an appropriate genotype (i.e., homozygous or hemizygous for recessives, heterozygous or hemizygous for dominants); for an autosomal dominant disorder, if only a proportion of people carrying the mutant allele display the abnormal phenotype, the trait is said to show incomplete penetrance. If all with the mutant allele show the abnormal phenotype, the trait is said to have complete or full penetrance. See: penetration.

penetrance

(pĕn′ĭ-trəns)
n.
The frequency, under given environmental conditions, with which a specific phenotype is expressed by those individuals with a specific genotype.

penetrance

Penetration The disruption of a surface, as in penetrating–eg, gunshot wounds, hospital-acquired penetration contact due to infected 'sharps', or forcible penetration in rape

pen·e·trance

(pen'ĕ-trăns)
The frequency, expressed as a fraction or percentage, of people who are phenotypically affected, among people of an appropriate genotype; factors affecting expression may be environmental, or due to purely random variation; contrasted with hypostasis where the condition has a genetic origin and therefore tends to cause correlation in relatives.

penetrance

The frequency with which a GENE manifests its effect. Failure to do so may result from the modifying effect of other genes or from environmental influences. A single hereditable dominant or recessive characteristic is either penetrant or not. Penetrance is measured as the proportion of individuals in a population with a particular genotype who show the corresponding PHENOTYPE.

penetrance

the percentage of individuals with a particular GENOTYPE that display the genotype in the PHENOTYPE. For example, a dominant gene for baldness is 100% penetrant in males and 0% penetrant in most females, because the gene requires high levels of the male hormone for expression, an example of SEX LIMITATION. Once a gene shows penetrance it may show a range of EXPRESSIVITY of phenotype.

penetrance 

The frequency with which the characteristics transmitted by a gene appear in individuals possessing it. Penetrance is represented as the ratio of individuals who carry the gene and express its effects, over the total number of carriers of the gene in a population. Few of the genes in the genome show a high penetrance because environmental factors play a role in development. Examples: familial exudative vitreoretinopathy and neurofibromatosis (type 1 and type 2), which are both inherited as autosomal dominant, have 100% penetrance; about 90% of the children who carry the retinoblastoma gene develop the disease while the gene remains non-penetrant in the remaining 10% of the children. See expressivity; familial exudative vitreoretinopathy.
References in periodicals archive ?
Microduplication 22811.2: a benign polymorphism or a syndrome with a very large clinical variability and reduced penetrance? Report of two families.
To determine cutoff [T.sub.m]s between allele classes, we plotted ROC curves by using the sizes of the CAG repeats (obtained by GeneScan analysis) and the [T.sub.m]s of the respective PCR products (obtained by PCR-MCA) as the test variables and using allele class (normal, intermediate, expanded with incomplete penetrance, or expanded with complete penetrance) as the classification variable.
Growing evidence supports the idea that more TG repeats increase the penetrance of the 5T allele as disease-causing mutation.
(6) Penetrance in familial cases also increases with age.
Hawkins said his literature review showed that "the penetrance of treatment of hypertension is what correlates to kidney disease, not the actual prevalence of hypertension in the population."
(1) The syndrome is characterized by complete penetrance but variable expressivity.
These findings suggest that "nongenetic factors may significantly influence the penetrance even of high-penetrance mutations," said Dr.
The inheritance pattern is autosomal-dominant, with incomplete expressivity and variable penetrance. Malignant lesions have also been reported, and they tend to be locally infiltrative.
Metropolitan areas were classified as high managed care market share if more than 30% of residents with health insurance belonged to a managed care plan or as areas of low managed care market share if penetrance was less than 10%.
This may also be explained by a germline mutation in a parent or autosomal dominant disease with reduced penetrance. The interpretation of the family histories may be further complicated by non-penetrance, age-related penetrance and variable expressivity, which may be features of familial DCM and appeared to be evident in the family pedigrees analysed.