PKU biology help question

Incidence

The incidence of PKU is about 1 in 15,000 births, but the incidence varies widely in different human populations from 1 in 4,500 births among the population of Ireland to 1 in 13,000 births in Norway to fewer than one in 100,000 births among the population of Finland. Turkey, at 1 in 2600, has the highest incidence rate in the world. The illness is also more common in Italy and China, as well as in Yemeni populations.
When both parents are carriers, there is:

A 1-in-4 (25 percent) chance that both will pass one abnormal PAH gene on to a child, causing the child to be born with PKU.
A 2-in-4 (50-50) chance that the baby will inherit one abnormal PAH gene from one parent and the normal gene from the other, making it a carrier like its parents.
A 1-in-4 (25 percent) chance that both parents will pass on the normal gene. The baby will neither have the disease nor be a carrier.
These chances are the same for each pregnancy.
Demographics

One in 50 individuals in the United States has inherited a gene for PKU. About 5 million Americans are PKU carriers. About one in 15,000 babies tests positive for PKU in the United States. Studies indicate that the incidence of this disease in Caucasian and Native American populations is higher than in African-American, Hispanic, and Asian populations.

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Thank you both!