Help! Dog afraid of her friendly owner.

[Positive Paws]

Help! This poor dog is terrified and her poor owner is heartbroken!
I am currently training a dog name Marcella, a 2-year old Italian Mastiff/ Cane Corso. She is a friendly dog, however, she is extremely timid. She was purchased from a reputable breeder about eight months ago by my client, who is a Doctor. The interesting part is that she acts very submissive and fearful around him—specifically. He has two small children that are kind of wild, and he has them every other weekend. Marcella acts as though their antics are normal and she is not afraid of them. She is shy around strangers and wary, as I would expect (she is a guarding breed that has had pathetically little socialization in her most important developmental periods.) However, her response to her owner exceeds this. Within five minutes of first meeting her, I was able to approach and have her approach me, feed treats from my hands, and pet her at will…something her owner is unable to do after eight months. Before we go any further, let me state with confidence that he has never (nope, not even once) hit her, punished her, or even scolded her. It can be assumed that she has had extremely little (or no) socialization until her current owner bought her. She is not playful, and remains in a state of constant stress. We have tried basic body language alterations, such as approaching slowly from the side, squatting without facing her, and looking away. She responds to these things, but painfully slow. She is still obviously uncomfortable with him approaching, and seems only to do it because she knows she is expected. She will take the treat and then casually get as far away as possible. He has been hand-feeding for about a week, and has been instructed to continue sitting in the floor and luring her close, then rewarding—all without making any sudden or scary movements. He smiles and speaks soothingly. Like I said, we are making some progress, but not nearly what I had hoped. It is quite obvious that something about her current owner reminds her strongly of a bad experience, and our handicap right now is not knowing what that something is. We have no way of knowing, and my client is (understandably) frustrated and troubled that his dog seems to abhor his existence and that after eight months she still cowers at his every move. I have been training for over five years professionally, and I know a lot about dogs, behavior, and training. Has anyone ever had experience here, because I’m a bit lost. Help and suggestions would be greatly appreciated. We have started working on a basic “come” cue, which she responded to well, so long as he was not standing and/or looking directly at her. She responds to his verbal “sit” command, albeit slowly and reluctantly. He cues her to “sit,” and she does so (all the while looking terrified…), at which point he is able to approach and leash/treat/whatever. So…HELP! 

[Redwine]

I am having a similar problem. My wife and I adopted a rescue dog in May. Zeke, a five year old Yorkie, and my wife get along great. They play, he gives her kisses and behaves like the young dog he is. When he sees me he runs into his kennel and hides.
Its been six months since we adopted him and while I have made a little progress with him, he is still very afraid of me. When we picked him up the rescue worker explained that Zeke got along with her, but not her husband.
I suspect Zeke may have been mistreated by a man.
I have tried approaching him sideways, with my back to him, on all fours, talking to him in a soothing tone of voice, giving him treats, etc. Once I get to the point where I pick him up and hold and petting him, he seems to be OK, then all of a sudden he will jump up and run back to his crate.
Any suggestions?