The phrase
"incomplete penetrance" refers to the situation when a genetic trait or disorder does not always appear in individuals who carry the gene or mutation associated with it. In other words, not everyone who has the gene will show the traits or symptoms of the gene.
Full definition
Inheritance
with incomplete penetrance means that other factors — other genes, gene regulators, and / or environment — are involved in the process that determines whether cataracts do or do not develop in any particular dog.
There are further complications, such
as incomplete penetrance, signs of X-linked disease in carrier females, and even a rare report of digenic inheritance.
The parent of an affected animal can be also be affected, due to the high gene frequency (thus, the apparent dominant inheritance), but this is not always the case (thus, the
apparent incomplete penetrance).
Not all affected breeds will be at risk to develop the DCM due to the fact that it
shows incomplete penetrance (does not show sign of disease despite having a copy of the mutation).
However, if it is found to have
incomplete penetrance genetically, it would still be possible for a dog to transmit the PHPV mutation without itself showing symptoms.
The mode of inheritance for most Aussie cataracts is dominant
with incomplete penetrance, meaning not every dog with the mutation will develop cataracts though 70 % of those with cataracts have it.
Because of
incomplete penetrance — because of healthy elderly carriers like Shonnie Medina's grandmother, Dorothy — the risk of cancer from 185delAG and other BRCA mutations must be expressed in terms of probability.
Incomplete penetrance, genetic heterogeneity, pleiotropy, and gene - environment interactions are just some of the factors that make even studies of relatively simple genetic diseases challenging.
The disease is referred to as having «
incomplete penetrance».
It must be noted however that a subset of PRA - affected Italian Greyhounds in the study carried only one copy of the IG - PRA1 risk allele, suggesting that the disease may represent a mode of inheritance called «Autosomal Dominant with
Incomplete Penetrance» (ADIP).
It is not known at this time whether the PRA observed in a minority of Carriers of the IG - PRA1 risk allele is due to another, as yet uncharacterized, form of PRA or whether IG - PRA1 is inherited as a dominant trait with
incomplete penetrance.
It should be noted that the human disease that mirrors CMR in dogs is an autosomal dominant disease with
incomplete penetrance.
In fact, many of the mutations that Embark screens are known to have
incomplete penetrance, meaning even if a dog is «At Risk» for a condition doesn't mean that it's a done deal and the dog will develop the health condition.
An autosomal recessive mode of inheritance, with
incomplete penetrance and a possible sex - predilection, most simply explains the segregation of epileptic dogs in the pedigrees examined.
A problem with some autosomal dominant disorders is
incomplete penetrance.
This genetic mutation has a characteristic called «
incomplete penetrance», which means that even if a dog has the mutation it may not penetrate and result in development of the disease.
Most, though not all inherited cataracts in Aussies appear to have be dominant with
incomplete penetrance.
The mode of inheritance for most Aussie cataracts is dominant with
incomplete penetrance, meaning not every dog with the mutation will develop cataracts.
Genes for diseases like this are often said to have
incomplete penetrance.
To further complicate the picture, the Aussie mutation is not a simple dominant; it is dominant with
incomplete penetrance.
Another type of gene that has
incomplete penetrance is the risk factor gene — a gene that will significantly increase risk of having the disease.
The mode of inheritance is most consistent with «autosomal dominance with
incomplete penetrance.»
Another way to describe this type of inheritance is «autosomal dominant with
incomplete penetrance» or «incomplete dominance».
At present there is no documentation that
incomplete penetrance is a factor in any canine deafness, except perhaps that deafness can affect one or both ears.
All of the above assumes that
incomplete penetrance is not acting.
These findings might be explained by a multi-gene cause - the presence of two different autosomal recessive deafness genes, or a syndrome with
incomplete penetrance.
This is an autosomal dominant disorder with
incomplete penetrance, which means that individuals that inherit the disorder may not show all components of the syndrome - i.e., they may not be deaf.
Mode of inheritance is unknown at this time, although some believe that it is autosomal dominant with
incomplete penetrance.
Essentially, what happens in utero to cause this is when a kitten inherited the autosomal dominant trait of the ZRS cic element of the PD gene with
an incomplete penetrance.
The mode of inheritance is unknown, but suspected to be either autosomal dominant with
incomplete penetrance, or autosomal recessive.
Dogs classified as having mild CM showed signs of affliction, but
the incomplete penetrance of the phenotype makes it impossible to include them in the affected category.