Which condition is commonly screened for in newborns using the Guthrie test?

The Guthrie test is specifically designed to screen newborns for phenylketonuria (PKU), a metabolic disorder that can lead to intellectual disability if left untreated. Phenylketonuria is caused by the deficiency of an enzyme required to metabolize the amino acid phenylalanine. Screening for PKU in newborns is crucial as early diagnosis and intervention can prevent the severe consequences associated with the condition. Choices B, C, and D are incorrect as the Guthrie test is not used to screen for cystic fibrosis, Down syndrome, or sickle cell anemia.