They are not the same but they are similar. This link can explain the nuances of using 'how' and 'what' much better than I... http://www.differencebetween.net/language/grammar-language/difference-between-how-and-what/

I usually use them interchangeably, this is especially true as a response. For example, if I asked "How are you?" you could reply either "I'm good, what about you?" or "I'm good, how about you?". In these kind of responses either is fine. I think the only difference is that How About is used to suggest ideas. For example, if we were in a restaurant and you didn't know what to eat, I could say "How about the fish?" as a suggestion. Hope this helps :)