In some cases I am fairly sure that G+T kids don't have SEN, but in others I'll beg to differ. I was without diagnosis for my entire school history, and I am now learning to cope with the fact that I have HFA. My children both show signs of being the same. Their intelligence comes with a flip side that means they have emotional and behavioural difficulties also.
My son taught himself to read in nursery, but he doesn't know how to interact socially very well and has a trigger hair temper when he doesn't know how to handle things. He also has difficulty with social communication, especially things like gratitude and says and does things that people can't understand, unless they know him like I do. He isn't rude, he is misunderstood because he finds expression difficult. He is very sensitive emotionally, and he needs to be in an environment where he can focus, which he doesn't manage very well. His teachers all express that he is dreamy and finds concentration difficult.
My daughter is behaviourally a bit of a nightmare. She wants what she wants and when she doesn't get it, she will behave in a very difficult way. I've had her brought home by the police aged four after working out how to get past extra locks and alarms put in place to stop her escaping. She went on a middle of the night jaunt and had (still has) no concept of danger or risk. She's destructive when she melts down, but socially she fares better than her brother because she is less passive and more in control. She does however do things that make people uncomfortable, too much physical contact, not respecting space, forgetting that there are other people in the classroom and everything does not revolve around her. She also barely sleeps and has a weird body clock, she'll happily wake at 2am and play for hours before school, then go to school and behave badly because she's tired.
They are both wonderful children, but they are also overwhelming. I had to give them to their fathers when I got made homeless, I'm disabled physically and I was getting to a point where I couldn't keep my daughter safe from herself any more. Intelligence is more than just being smart, it can come with difficulties, and since I've lived that, I aim to ensure my children don't turn out the same way as I do.