Transmission of an Incomplete Autosomal Dominant
Genetic Disease in Dogs
What does incomplete autosomal dominant mean?
Incomplete autosomal dominant is a term used to describe a type of genetic transmission in which a mutation in an autosomal gene (i.e., not located on the sex chromosomes) can cause a disease or trait even if only one copy of the gene is mutated. However, in the case of incomplete dominance, the clinical presentation or symptoms may vary in intensity among individuals carrying the mutation.
Key points to better understand this concept:
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Incomplete penetrance: Not all individuals carrying the mutation will necessarily show symptoms of the disease. For example, a dog may carry an autosomal dominant genetic mutation but never develop the disease, or may only show mild symptoms.
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Variable expressivity: Symptoms can vary in severity among affected individuals. One dog may have severe clinical signs, while another carrying the same mutation may show only mild signs or remain completely asymptomatic.
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Concrete example: Suppose a dog has a mutation in an autosomal dominant gene that causes a disease with incomplete penetrance. If this dog is bred with a healthy dog, there is a 50% chance that each puppy will inherit the mutation. However, among those that inherit the mutation, some may show severe signs of the disease, others mild signs, and some may not show any clinical signs at all.
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Implications for breeding: Incomplete dominance makes predicting the outcome of breeding more challenging, since even genetic testing cannot guarantee whether a dog carrying the mutation will develop symptoms, or how severe they may be.
In summary, incomplete autosomal dominant inheritance means that a single copy of a mutated gene can cause a disease, but the presence and severity of symptoms can vary widely among affected individuals.
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