With gifted children, why do we see these so often: perfectionism, anxiety, sensitivity, sensory issues, difficulty with anger management?

Do these just go hand in hand with giftedness? Is it related to asynchronoous development? Is it neurological? Does it have something to do with heightened development of certain ares of the brain? Is it chemical? What's the link?

Sorry for my ignorance, but I'd really like to understand the physiology behind this connection. Thanks!