Tegan Webb was diagnosed shortly after birth with mucolipidosis, an extremely rare genetic syndrome that dramatically shortens life expectancy.

It is a progressively debilitating disorder that affects many parts of the body.

Most of those who have mucolipidosis do not survive past their early childhood.

But Tegan has beaten the odds and her family consider her a miracle.

About 100 family and friends gathered at the Howlong Community Centre on Saturday to celebrate the milestone, five days ahead of her actual birthday on Thursday.

Mum Sylvia Webb said her daughter was believed to be the oldest person in the world with the syndrome.

“She’s our amazing little miracle,” she said.

Tegan’s party had been two years in the making.

“We told her she could have a big 30th two years ago,” Mrs Webb said.

“She has been inviting people for the past two years.”

Tegan was not shy in telling people “it’s my special day”.

“She likes to be the centre of attention, like most girls,” Mrs Webb said.

“She is also a girly girl and loves handbags and clothes.”

Her father, Charles, was a proud dad, describing his daughter as bubbly and outgoing.

“She is very strong and she is a fighter.”

Tegan is the second eldest among her siblings. Her eldest sister, Jade, suffered from mucolipidosis and died at 21.

Her late brother Lucas and sister Faith were also sufferers, losing their battles to survive at 21 and 14 respectively.

Lucas’ twin, Caryl, 28, does not have the disorder, nor does their brother Christian, 25.

Tegan has one remaining sibling with the syndrome, Grace, who is 16.