IN Jervis's introductory study, and in subsequent case reports of phenylketonuria (phenylpyruvic oligophrenia), a blonde hair colour and a fair skin have been noted in the large majority of the ...

The intensity of hair color depends on the density of pigment within the melanosome. Both eumelanin and pheomelanin are made from the amino acid tyrosine, using the enzyme tyrosinase. Increased ...