What describes the impact of environmental factors on genetic diseases like PKU?

• A. Environment has no impact
• B. Environment enhances genetic expression
• C. Environment strongly influences health outcomes
• D. Environment only affects phenotypic traits

Answer: (C)

The correct response indicates that environmental factors have a significant influence on the health outcomes related to genetic diseases like phenylketonuria (PKU). PKU is an inherited metabolic disorder that results from a deficiency in the enzyme phenylalanine hydroxylase, which is essential for converting the amino acid phenylalanine into tyrosine. If individuals with PKU consume foods high in phenylalanine, such as meat or dairy products, this can lead to severe neurological damage and developmental issues.

The environment plays a critical role in this context, particularly through dietary choices. A person with PKU must adhere to a strict low-phenylalanine diet to prevent the harmful effects of the disease. Thus, while the genetic mutation is the underlying cause of PKU, environmental factors—such as food consumption—are crucial in determining health outcomes. This illustrates the interplay between genetic predisposition and environmental factors in managing genetic diseases, emphasizing that simply having the genetic trait does not solely dictate health outcomes; rather, how one interacts with their environment can profoundly influence their condition.