Ms Trepak, also mum to Ella-Mae, 12, Bradlee, 10, Archie, six and four-year-old Poppy, said: "She had bad colic and her hair didn't grow. She had no hair until she was about four-and-a-half.
“People called her a boy all the time."
Olivia who is 'conditioned' to eat is a happy child at home but can suffer from violent outbursts, her mum said.
She said: ”She doesn't let any of this affect her - because for her, she's normal. She's never experienced pain, or hunger, or tiredness.
"But it was such a battle for us to find out what was causing her symptoms. The doctors had no idea what could be wrong with her.
"To look at Olivia you don't know anything's wrong with her. I want people to know and to stop judging. I want to raise awareness or chromosome 6 problems."
Olivia and her mum have been supported by chromosome disorder support group Unique.
About one in 200 babies is born with a rare chromosome disorder but each one can be very different, making them exceptionally rare.