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

/pen·e·trance/ (pen´ĭ-trins) the frequency with which a heritable trait is manifested by individuals carrying the principal gene or genes conditioning it.

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

[pen′ətrəns]
Etymology: L, penetrare, to penetrate
the regularity with which an allele is expressed in a person who carries it. If an allele always produces its effect on the phenotype, it is fully penetrant. Achondroplasia is caused by a fully penetrant allele; if the allele is present, achondroplasia results. If an allele produces its effect less frequently than 100% of the time, it is not fully penetrant. Retinoblastoma develops in 90% of the children carrying the allele for the disease; in 10% of children the allele is nonpenetrant. penetrant, adj.

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.

penetrance

the frequency with which a heritable trait is manifested by individuals carrying the principal gene or genes conditioning it.

incomplete penetrance
when penetrance is less than 100%.
References in periodicals archive ?
The laboratory must take into account disease severity, penetrance, expected age of onset, locus heterogeneity, and other factors.
Approximately half of AC cases are considered to be familial, most frequently in an autosomal-dominant fashion with variable penetrance.
Schiestl (2013) Intestinal bacteria modify lymphoma penetrance in genetically susceptible mice via inflammation-mediated systemic host oxidative stress and leucocyte genotoxicity-Cancer Research 73(14):4222-4232 July 15, 2013 PMCID: PMC3718495; Katrin Hacke, Akos Szakmary, Andrew R.
Ugur and Tolun 26 reported a multi generation consanguineous Turkish family having autosomal recessive inheritance with reduced penetrance showing typical SHFM phenotypes.
Koch, professor of pediatric neurology at the Medical University of South Carolina, Charleston, described tuberous sclerosis (TSC) as an autosomal dominant disorder with variable penetrance.
Polymorphisms of Low Penetrance Genes as Genetic Markers of Risk of Familial Breast Cancer among Colombian Women
A simple autosomal recessive and dominant gene with incomplete penetrance have been reported to be linked with hydrocephalus in cattle.
AACE/ACE leaders pointed out that today there are better tools to treat obesity than ever before, including improvements in lifestyle intervention, new medications, and improvements in bariatric surgery, yet there's limited access and penetrance of these tools in the clinic.
Tuberous sclerosis is an autosomal-dominant disease with variable penetrance that affects approximately 40,000 individuals in the United States and 2 million people worldwide.
It is an autosomal dominant condition inherited with variable expression and reduced penetrance.
This disorder may be inherited with variable penetrance or may be acquired because of liver dysfunction.