The pair will leave the U17 residency in Florida to sign multi-year contracts with Hoffenheim, according to agent Dan Segal.
15-year old Renken has been labelled as the 'next big thing' in US football and has attracted interest from several Premier League clubs whilst 16-year old Gyau has already undergone a trial with German giants Bayern Munich.
Segal revealed the decision to join Hoffenheim.
"The key to the decision made by the boys and their families is that Hoffenheim constructed an outstanding path for their development as players," Segal said.
"During their first year, they will be permitted to split time between Germany and Vancouver, where they will attend school and be trained to prepare for a full-time adjustment to Germany the following year.
"Thereafter, they will be part of one of the best youth systems in the world at a club that emphasizes the promotion of youth players," Segal added.
"Charles and Joe know that their best years are ahead of them, and this program will give them the best chance to achieve their great potential."