The parents of a terminally-ill youngster who has just turned six said she is defying all the odds.

Tess Sullivan celebrated her sixth birthday at White Ash Special School in Oswaldtwistle. The celebration continued into the weekend at the Chill Factore in Manchester.

Tess, who is one of 50 infants in the world to have the degenerative disorder Alexander disease, is doing really well, according to her mum and dad Helen and Steve Sullivan.

But Helen, 33, of Bluebell Way, Huncoat, said celebrating Tess’s birthdays does bring with it a lot of mixed emotions.

She said: “We were looking at baby photos of Tess recently, ones when she was two or three months old. At that time we never thought she would become ill.

“But then, after she was diagnosed, we never thought we would be celebrating her sixth birthday. Tess is doing very well considering and is defying all the odds.”

She added: “We do think ‘how many more birthdays are we going to have with her?’, but we are also very grateful to have this birthday to celebrate.

Almost £14,000 has been raised for the Tess Sullivan Campaign since it was launched by the Observer in 2009.

Tess, who turned six on Thursday, January 24, underwent surgery to remove parts of her skull after being diagnosed with pressure to the brain.

The youngster, who lives with dad Steve, 45, mum Helen and brothers Tyler, 15, and Max, three, was recently a bridesmaid at the wedding of a young couple who have been inspired by her courage.

Tess also spent a few days at Derian House Children’s Hospice in Chorley over the festive period, after she had a seizure in November.