When considering genetic conditions in a pediatric patient, what is the chance that a woman with a father affected by Huntington disease will inherit the abnormal gene?

A woman with a father affected by Huntington disease has a 50% chance of inheriting the abnormal gene because Huntington disease follows an autosomal dominant inheritance pattern. In autosomal dominant conditions, only one copy of the mutated gene is required for an individual to express the disease.

In this scenario, the father, who has Huntington disease, possesses one normal allele and one mutant allele at the gene responsible for the condition. When he has children, each child has a 50% chance of inheriting the mutant allele because they have an equal likelihood of receiving either the normal or the mutated copy from their affected parent.

This genetic mechanism means that the daughter in question has a 50% probability of being a carrier of the Huntington disease gene and, if she inherits the mutant allele, she will go on to express the disease as well. Understanding the mode of inheritance and probability is crucial in genetics, especially when assessing risks in familial conditions like Huntington disease.