Why did April become a red head in all media outside of the comics?

[Original TMNT Cartoon Fan]

Originally Posted by Luzmagica

Yep...You are right...I had read about Mirage "April o´Neil" was actually supposed to be dark and curly hair....Also I had read about a misunderstanding with her surname "O´Neil" that its an Irish surname, and so they change to and Irish red look girl for Miss O´Neil...

And Irma must be some German-American, Austrian-American or German speaking Swiss-American or something. The name Irma exists here in Sweden too, but her last name Langinstein is from the German language.