B Sc III phenylketonuria PKU

Read following links 

http://learn.genetics.utah.edu/content/disorders/singlegene/pku/

http://www.pku.com/en/What_is_PKU/Understanding_the_science_of_PKU/understanding_the_science_of_pku.html

http://newenglandconsortium.org/for-families/phenylketonuria-pku/pku-primer-for-adolescents-and-adults/

https://www.genome.gov/25020037