What is true about an autosomal dominant disorder?

An autosomal dominant disorder is characterized by the fact that only one mutated copy of the gene is sufficient to cause the disorder. This means that an individual who has one normal copy of the gene and one mutated copy will typically express the phenotype associated with the disorder. This is due to the dominant nature of the mutated allele, which masks the effect of the normal allele.

In the context of inheritance patterns, this allows for the possibility that an affected individual can pass the disorder to their offspring, even if the other parent does not carry the mutation. Each child of an affected individual has a 50% chance of inheriting the mutated gene and, therefore, the disorder.

Understanding this concept is crucial for genetic counseling and predicting the likelihood of passing on the disorder to future generations. This distinguishes autosomal dominant disorders from those that require two copies of the mutated gene (recessive disorders) for the individual to express the condition.