If a parent has a heterozygous pathogenic variant for an autosomal dominant disorder with full penetrance, what is the probability that each child inherits the variant?

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In autosomal dominant inheritance, a single mutant allele can cause the disorder. A heterozygous parent has one normal and one mutant allele, and for each pregnancy, passes on either allele with equal probability. If the other parent is unaffected, they contribute a normal allele, so each child has a 50% chance of inheriting the mutant variant and a 50% chance of inheriting the normal one. Full penetrance means anyone who inherits the variant will express the disease, but it does not change the inheritance probability. So the chance per child to inherit the variant is 50%.