In autosomal dominant diseases with incomplete penetrance, which statement best describes recurrence risk counseling?

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Multiple Choice

In autosomal dominant diseases with incomplete penetrance, which statement best describes recurrence risk counseling?

Incomplete penetrance means that not every person who carries a disease-causing allele actually shows the disease. Because of this, a parent who looks healthy may still be a carrier and pass the allele to their children. In counseling, that possibility must be considered, since a healthy-appearing parent could contribute a 50% risk to each child if they are indeed a carrier. So the best statement is that a parent who carries the pathogenic allele may appear unaffected due to incomplete penetrance. The other options ignore how penetrance alters the interpretation of a parent’s phenotype and the associated recurrence risk.

Incomplete penetrance means that not every person who carries a disease-causing allele actually shows the disease. Because of this, a parent who looks healthy may still be a carrier and pass the allele to their children. In counseling, that possibility must be considered, since a healthy-appearing parent could contribute a 50% risk to each child if they are indeed a carrier. So the best statement is that a parent who carries the pathogenic allele may appear unaffected due to incomplete penetrance. The other options ignore how penetrance alters the interpretation of a parent’s phenotype and the associated recurrence risk.

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