Student or Learner
In case of a personal letter to father or mother, a son or daughter can write "yours affectionately Tom ( or Jenny)", but what parents can write to their children's letter in the closing section.
I don't know properly the forms used in the closing section and thus can't explain properly.
From children to their Parents
Salutation -> My dear daddy / mummy and Closing -> Yours affectionately Tom or Jenny
Form Parents to their Children
Salutation -> My dear Tom / Jenny and Closing -> ???????