Final answer:
The statement regarding CHARGE syndrome's occurrence is false. The genetic patterns of inheritance for an autosomal recessive disorder like cystic fibrosis involve a 25% chance of both parents who are carriers having an affected child. X-linked and autosomal dominant disorders have different inheritance probabilities.
Step-by-step explanation:
The claim that CHARGE syndrome has an occurrence of 1-2% in parents who are not affected by the condition is false. CHARGE syndrome is a rare genetic disorder, and for autosomal recessive diseases like cystic fibrosis, which is often used as an example to explain these types of inheritance patterns, the chances of having an affected child when both parents are carriers are different. According to the rules of inheritance, two parents who are carriers for an autosomal recessive disorder (represented as Ff in relation to the cystic fibrosis gene), have a 25% chance of having a child with the disease (ff), 50% chance that their child will be a carrier (Ff), and 25% chance that the child will not carry the disease allele at all (FF).
Situations involving other inheritance patterns, such as X-linked disorders, or autosomal dominant disorders like Marfan syndrome, have different probabilities and implications for carriers and affected individuals. For an X-linked recessive disorder, if a mother is a carrier, her sons have a 50% chance of being affected, and daughters have a 50% chance of being carriers. In the case of autosomal dominant disorders, such as Marfan syndrome, there is no carrier state as such, since inheriting just one allele for the trait will result in the individual being affected.